Migrate test block 47 and downstream dependencies to Dart 2.0.

tests/language_2/generic_constructor_mixin2_test.dart

Index: tests/language_2/generic_constructor_mixin2_test.dart
diff --git a/tests/language_strong/generic_constructor_mixin2_test.dart b/tests/language_2/generic_constructor_mixin2_test.dart
similarity index 81%
rename from tests/language_strong/generic_constructor_mixin2_test.dart
rename to tests/language_2/generic_constructor_mixin2_test.dart
index f1ca388534f02f8b10bbb73cd772c6afc75314aa..7a7095b20344863ff5d8c0d32b6449a3980ecc1e 100644
--- a/tests/language_strong/generic_constructor_mixin2_test.dart
+++ b/tests/language_2/generic_constructor_mixin2_test.dart
@@ -5,7 +5,7 @@
 // Test that parameter types types are checked correctly in the face of
 // mixin application upon a generic constructor.
 
-import 'checked_mode_helper.dart';
+import 'dynamic_type_helper.dart';
 
 class A<X> {
   A(X x);
@@ -20,5 +20,5 @@ class D<Y> = A<Y> with B, C;
 void main() {
   var v = 0;
   checkNoDynamicTypeError(() => new D<int>(v));
-  checkDynamicTypeError(() => new D<String>(v));
+  checkDynamicTypeError(() => new D<String>(v)); //# 01: compile-time error
 }