Ensure ICU is fully linked out in invariant mode

[CoffeeFlux]

This is enabled by other work we're doing as part of .NET 6, but we should add assertions in addition to that to make sure everything really is going away.

We should be able to create a new project with the latest SDK, set the following properties, and have the native ICU bits fall away:

    <InvariantGlobalization>true</InvariantGlobalization>
    <WasmBuildNative>true</WasmBuildNative>

[lewing]

To do this we need to be able to scan the linked assemblies for qcalls and we are running into #43791

[lewing]

qcall linking should be in #43798 what is the status here?

cc @vargaz @EgorBo

[vargaz]

This will be solved when pinvoke linking is enabled since the icall qcalls are treated as pinvokes.
However, the icu data/startup code still needs to be disabled.

[CoffeeFlux]

I wanted this as a separate issue to add checks to make sure it's not getting included, though like Zoltan said this is dependent on #43783 before it has a chance.

[vargaz]

This should work now, set the InvariantGlobalization and WasmBuildNative msbuild properties to true.

[marek-safar]

@vargaz does it work for interpreter mode?

[vargaz]

Yes.

[CoffeeFlux]

At what point will I be able to replicate this with a nightly SDK drop? Does Blazor need to pick up runtime changes, or should this work right now? And if so, what exactly do I need to do in order to see it work - just make a new blazorwasm project and set WasmBuildNative in the csproj?

[marek-safar]

Blazor need to pickup new runtime pack and then you set InvariantGlobalization msbuild property