Fix dart2js warnings and add test to ensure it stays clean.

pkg/testing/lib/src/test_dart/status_file_parser.dart

 // 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.
 
-library status_file_parser;
+library test_dart_copy.status_file_parser;
 
 import "dart:async";
 import "dart:convert" show LineSplitter, UTF8;
 import "dart:io";
 
 import "path.dart";
 import "status_expression.dart";
 
 import '../expectation.dart' show Expectation, ExpectationSet;
 
@@ skipping 225 matching lines @@
         }
         regExps[i] = regExp;
       }
       _keyToRegExps[key] = regExps;
     });
 
     _regExpCache = null;
     _preprocessed = true;
   }
 }