Change simpleName of anonymous mixin applications.

dart/tests/lib/mirrors/hierarchy_test.dart

 // Copyright (c) 2013, 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.
 
 library hierarchy_test;
 
 @MirrorsUsed(targets: 'hierarchy_test, Object')
 import 'dart:mirrors';
 
 import 'package:expect/expect.dart';
@@ skipping 27 matching lines @@
 }
 
 main() {
   Expect.stringEquals('''
 > hierarchy_test.Bar
   + hierarchy_test.FooMixin
 > hierarchy_test.Qux
 > dart.core.Object
 ''', stringifyHierarchy(reflect(new Bar()..foo()..bar()..qux())));
 
-  // TODO(ahe): Using wrong mixin syntax, see http://dartbug.com/12464.
   Expect.stringEquals('''
 > hierarchy_test.Baz
-> hierarchy_test.FooMixin(hierarchy_test.Qux)
+> hierarchy_test.Qux with hierarchy_test.FooMixin
   + hierarchy_test.FooMixin
 > hierarchy_test.Qux
 > dart.core.Object
 ''', stringifyHierarchy(reflect(new Baz()..foo()..bar()..qux())));
 }