Migrate test block 47 and downstream dependencies to Dart 2.0.

tests/language_2/generic_constructor_mixin_test.dart

 // Copyright (c) 2014, 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.
 
 // 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);
 }
 
 class B {}
 
 class C<Y> = A<Y> with B;
 
 void main() {
   var v = 0;
   checkNoDynamicTypeError(() => new C<int>(v));
-  checkDynamicTypeError(() => new C<String>(v));
-}
+  checkDynamicTypeError(() => new C<String>(v)); //# 01: compile-time error
+}