Fix Mac path to DumpRenderTree in dart test scripts.

tools/testing/dart/test_suite.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("test_suite");
 
 #import("status_file_parser.dart");
 #import("test_runner.dart");
 #import("multitest.dart");
 
@@ skipping 392 matching lines @@
   }
 
   static String get scriptType() => 'application/dart';
 
   String getHtmlName(String filename) {
     return filename.replaceAll(pathSeparator, '_') + 'dartium.html';
   }
 
   static String get dumpRenderTreeFilename() {
     if (new Platform().operatingSystem() == 'macos') {
-      return 'client/tests/drt/.app/Contents/MacOS/DumpRenderTree';
+      return 'client/tests/drt/DumpRenderTree.app/Contents/' +
+          'MacOS/DumpRenderTree';
     } 
     return 'client/tests/drt/DumpRenderTree';
   }
 
 
   void testGeneratorStarted() {
     ++activeTestGenerators;
   }
 
   void testGeneratorDone() {
@@ skipping 299 matching lines @@
  * $noCrash tests are expected to be flaky but not crash
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout\
 """;
     print(report);
   }
 }