test: move tests requiring the VM to their own test file

Fixes https://github.com/dart-lang/typed_data/issues/16

test/int64_test.dart

@@ -689,24 +689,6 @@ void main() {
       expect(new Int64(4503599627370496).toInt(), 4503599627370496);
       expect(new Int64(-4503599627370495).toInt(), -4503599627370495);
       expect(new Int64(-4503599627370496).toInt(), -4503599627370496);
-      expect(Int64.parseInt("-10000000000000000").toInt(),
-          same(-10000000000000000));
-      expect(Int64.parseInt("-10000000000000001").toInt(),
-          same(-10000000000000001));
-      expect(Int64.parseInt("-10000000000000002").toInt(),
-          same(-10000000000000002));
-      expect(Int64.parseInt("-10000000000000003").toInt(),
-          same(-10000000000000003));
-      expect(Int64.parseInt("-10000000000000004").toInt(),
-          same(-10000000000000004));
-      expect(Int64.parseInt("-10000000000000005").toInt(),
-          same(-10000000000000005));
-      expect(Int64.parseInt("-10000000000000006").toInt(),
-          same(-10000000000000006));
-      expect(Int64.parseInt("-10000000000000007").toInt(),
-          same(-10000000000000007));
-      expect(Int64.parseInt("-10000000000000008").toInt(),
-          same(-10000000000000008));
     });
 
     test("toInt32", () {
@@ -763,8 +745,6 @@ void main() {
     check(10);
     check(1000000000000000000);
     check(9223372000000000000); // near Int64.MAX_VALUE, has exact double value
-    check(9223372036854775807); // Int64.MAX_VALUE, rounds up to -MIN_VALUE
-    check(-9223372036854775808); // Int64.MIN_VALUE
   });
 
   group("parse", () {

test/int_64_vm_test.dart

@@ -0,0 +1,47 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@TestOn('!js')
+
+import 'package:fixnum/fixnum.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group("conversions", () {
+    test("toInt", () {
+      expect(Int64.parseInt("-10000000000000000").toInt(),
+          same(-10000000000000000));
+      expect(Int64.parseInt("-10000000000000001").toInt(),
+          same(-10000000000000001));
+      expect(Int64.parseInt("-10000000000000002").toInt(),
+          same(-10000000000000002));
+      expect(Int64.parseInt("-10000000000000003").toInt(),
+          same(-10000000000000003));
+      expect(Int64.parseInt("-10000000000000004").toInt(),
+          same(-10000000000000004));
+      expect(Int64.parseInt("-10000000000000005").toInt(),
+          same(-10000000000000005));
+      expect(Int64.parseInt("-10000000000000006").toInt(),
+          same(-10000000000000006));
+      expect(Int64.parseInt("-10000000000000007").toInt(),
+          same(-10000000000000007));
+      expect(Int64.parseInt("-10000000000000008").toInt(),
+          same(-10000000000000008));
+    });
+  });
+
+  test("", () {
+    check(int n) {
+      // Sign change should commute with conversion.
+      expect(-new Int64(-n), new Int64(n));
+      expect(new Int64(-n), -new Int64(n));
+    }
+
+    check(10);
+    check(1000000000000000000);
+    check(9223372000000000000); // near Int64.MAX_VALUE, has exact double value
+    check(9223372036854775807); // Int64.MAX_VALUE, rounds up to -MIN_VALUE
+    check(-9223372036854775808); // Int64.MIN_VALUE
+  });
+}