Migrate test block 47 and downstream dependencies to Dart 2.0.

tests/language_2/typevariable_substitution2_test.dart

Index: tests/language_2/typevariable_substitution2_test.dart
diff --git a/tests/language/typevariable_substitution2_test.dart b/tests/language_2/typevariable_substitution2_test.dart
similarity index 81%
rename from tests/language/typevariable_substitution2_test.dart
rename to tests/language_2/typevariable_substitution2_test.dart
index 4cd858ad81163406d60880fa7ed9abadcbc53550..fb33977303b7722c4d3f2a7faaaab33fbd844433 100644
--- a/tests/language/typevariable_substitution2_test.dart
+++ b/tests/language_2/typevariable_substitution2_test.dart
@@ -4,7 +4,7 @@
 
 // Test that mixins don't interfere with type variable substitution.
 
-import 'checked_mode_helper.dart';
+import 'dynamic_type_helper.dart';
 
 class B<T> {
   B(T x);
@@ -21,5 +21,5 @@ class C<T> = B<T> with M;
 main() {
   new A(null);
   new C<String>(''); //# 01: ok
-  checkDynamicTypeError(() => new C<String>(0)); //# 02: static type warning
+  checkDynamicTypeError(() => new C<String>(0)); //# 02: compile-time error
 }