Added support for skipping redundant dart2js compilations.

tests/standalone/io/test_runner_exit_code_script.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.
 
 // Simulates a use of test_progress during a failing run of test.dart.
 
 #import("../../../tools/testing/dart/test_progress.dart");
 #import("../../../tools/testing/dart/test_runner.dart");
 #import("../../../tools/testing/dart/test_options.dart");
 
@@ skipping 10 matching lines @@
                               [dummyCommand],
                               configuration,
                               (_) => null,
                               new Set<String>.from(['PASS']));
 
   // Simulate the test.dart use of the progress indicator.
   progress.testAdded();
   progress.allTestsKnown();
   progress.start(testCase);
   new CommandOutput.fromCase(testCase, dummyCommand, 1, false, false, [], [],
-                             new Date.now().difference(startTime));
+                             new Date.now().difference(startTime), false);
   progress.done(testCase);
   progress.allDone();
 }