Clean up usings in test cases assembly (#88678)

The main goal here is to get rid of the unused `System.Linq` usings.  These cause problems for our UnityLinker tests that run against mono class libraries as it requires an additional reference.  We could work around it by referencing everything in the mono class libraries, which is what illink does during it's tests.  That said, some of the files had a lot of unnecessary usings and I don't think it's a bad thing to clean them up anyways.

Rather than hunt down the 10-20 files that were problematic I ran Rider's namespace clean up functionality on `Mono.Linker.Tests.Cases`

src/tools/illink/test/Mono.Linker.Tests.Cases/Advanced/TypeCheckRemovalDisabled.cs

@@ -1,4 +1,3 @@
-using System;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes.Debugger/KeepDebugMembers/DebuggerDisplayAttributeOnGenerics.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes.StructLayout/AutoClass.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Runtime.InteropServices;
+using System.Runtime.InteropServices;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Attributes.StructLayout

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes.StructLayout/ExplicitClass.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Runtime.InteropServices;
+using System.Runtime.InteropServices;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Attributes.StructLayout

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes.StructLayout/UnusedTypeWithSequentialLayoutIsRemoved.cs

@@ -1,5 +1,4 @@
 using System.Runtime.InteropServices;
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Attributes.StructLayout
 {

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/AssemblyAttributeIsRemovedIfOnlyTypesUsedInAssembly.cs

@@ -1,5 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Attributes.Dependencies;
+using Mono.Linker.Tests.Cases.Attributes.Dependencies;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/AttributeOnAssemblyIsKeptIfDeclarationIsSkipped.cs

@@ -1,6 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Attributes;
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 #if REFERENCE_INCLUDED

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/FixedLengthArrayAttributesArePreserved.cs

@@ -1,5 +1,4 @@
 using System.Runtime.CompilerServices;
-using System.Security;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/GenericAttributes.cs

@@ -1,6 +1,5 @@
 using System;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
-using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.Attributes
 {

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/MarshalAsCustomMarshaler.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Runtime.InteropServices;
-using System.Text;
+using System.Runtime.InteropServices;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Attributes

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/MarshalAsCustomMarshalerInterface.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Runtime.InteropServices;
-using System.Runtime.Serialization;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/OnlyKeepUsed/AttributeDefinedAndUsedInOtherAssemblyIsKept.cs

@@ -1,5 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Attributes.OnlyKeepUsed.Dependencies;
+using Mono.Linker.Tests.Cases.Attributes.OnlyKeepUsed.Dependencies;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/OnlyKeepUsed/CanLinkCoreLibrariesWithOnlyKeepUsedAttributes.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Timers;
+using System.Timers;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/OnlyKeepUsed/UnusedAttributeWithTypeForwarderIsRemoved.cs

@@ -1,5 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Attributes.OnlyKeepUsed.Dependencies;
+using Mono.Linker.Tests.Cases.Attributes.OnlyKeepUsed.Dependencies;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/SecurityAttributesOnUsedMethodAreKept.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Security.Permissions;
+using System.Security.Permissions;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Attributes/SecurityAttributesOnUsedTypeAreKept.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Security.Permissions;
+using System.Security.Permissions;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/BCLFeatures/ETW/BaseRemovedEventSource.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Diagnostics.Tracing;
+using System.Diagnostics.Tracing;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/BCLFeatures/ETW/Excluded.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Diagnostics.Tracing;
+using System.Diagnostics.Tracing;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/BCLFeatures/ETW/StubbedMethodWithExceptionHandlers.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Diagnostics.Tracing;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/DelegateBeginInvokeEndInvokePair.cs

@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Basic

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/LinkerHandlesRefFields.cs

@@ -2,12 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Runtime.CompilerServices;
-using System.Text;
-using System.Threading.Tasks;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/MultiLevelNestedClassesAllRemovedWhenNonUsed.cs

@@ -1,6 +1,4 @@
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
-
-namespace Mono.Linker.Tests.Cases.Basic
+namespace Mono.Linker.Tests.Cases.Basic
 {
 	class MultiLevelNestedClassesAllRemovedWhenNonUsed
 	{

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/UnusedDelegateGetsRemoved.cs

@@ -1,6 +1,4 @@
-using System;
-
-namespace Mono.Linker.Tests.Cases.Basic
+namespace Mono.Linker.Tests.Cases.Basic
 {
 	class UnusedDelegateGetsRemoved
 	{

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/UnusedEnumGetsRemoved.cs

@@ -1,6 +1,4 @@
-using System;
-
-namespace Mono.Linker.Tests.Cases.Basic
+namespace Mono.Linker.Tests.Cases.Basic
 {
 	class UnusedEnumGetsRemoved
 	{

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/UnusedEventGetsRemoved.cs

@@ -1,5 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Basic
 {

src/tools/illink/test/Mono.Linker.Tests.Cases/Basic/UsedEnumIsKept.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Reflection;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.Basic

src/tools/illink/test/Mono.Linker.Tests.Cases/CodegenAnnotation/ReflectionBlockedTest.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Reflection;
+using System.Reflection;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/CoreLink/CopyOfCoreLibrariesKeepsUnusedTypes.cs

@@ -1,5 +1,4 @@
-using System;
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/CoreLink/LinkingOfCoreLibrariesRemovesUnusedMethods.cs

@@ -1,6 +1,4 @@
-using System;
-using System.Collections;
-using System.IO;
+using System.Collections;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;

src/tools/illink/test/Mono.Linker.Tests.Cases/CoreLink/LinkingOfCoreLibrariesRemovesUnusedTypes.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;

src/tools/illink/test/Mono.Linker.Tests.Cases/CppCLI/CppCLIAssemblyIsAnalyzed.cs

@@ -1,9 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
-using System.IO;
-using System.Runtime.InteropServices;
 using Mono.Linker.Tests.Cases.CppCLI.Dependencies;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;

src/tools/illink/test/Mono.Linker.Tests.Cases/CppCLI/NonCopyActionWarnOnCppCLI.cs

@@ -1,9 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
-using System.IO;
-using System.Runtime.InteropServices;
 using Mono.Linker.Tests.Cases.CppCLI.Dependencies;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/AnnotatedMembersAccessedViaReflection.cs

@@ -2,13 +2,9 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Runtime.InteropServices;
-using System.Text;
-using System.Threading.Tasks;
 using Mono.Linker.Tests.Cases.DataFlow;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ApplyTypeAnnotations.cs

@@ -2,9 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/AssemblyQualifiedNameDataflow.cs

@@ -2,9 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/AttributeConstructorDataflow.cs

@@ -2,10 +2,8 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/AttributeFieldDataflow.cs

@@ -2,10 +2,8 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/AttributePropertyDataflow.cs

@@ -2,10 +2,8 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
-using System.Text;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeAccessedViaReflection.cs

@@ -4,12 +4,8 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Linq.Expressions;
 using System.Runtime.InteropServices;
-using System.Text;
 using System.Threading.Tasks;
-using Mono.Linker.Tests.Cases.DataFlow;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeInPreservedAssembly.cs

@@ -1,11 +1,8 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
-using Mono.Linker.Tests.Cases.Expectations.Helpers;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeInPreservedAssemblyWithWarning.cs

@@ -1,11 +1,8 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
-using Mono.Linker.Tests.Cases.Expectations.Helpers;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedTypesRelease.cs

@@ -1,11 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-using System.Reflection;
-using System.Threading.Tasks;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Metadata;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ComplexTypeHandling.cs

@@ -2,11 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 
 namespace Mono.Linker.Tests.Cases.DataFlow

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ConstructedTypesDataFlow.cs

@@ -2,11 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Mono.Linker.Tests.Cases.Expectations.Helpers;
 

src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/Dependencies/Library.cs

@@ -2,11 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Mono.Linker.Tests.Cases.DataFlow.Dependencies
 {