cleanup to tools/testing/dart

tools/testing/dart/lib/browser_test.dart

 // Copyright (c) 2011, 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 browser_test;
 
 import 'path.dart';
 
 String getHtmlContents(String title,
                        String scriptType,
@@ skipping 31 matching lines @@
   return """
 import '$libraryPathComponent' as test;
 
 main() {
   print("dart-calling-main");
   test.main();
   print("dart-main-done");
 }
 """;
 }