Migrated test block 27 to Dart 2.0.

tests/corelib_2/stopwatch_test.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.
 
 // Dart test program for testing stopwatch support.
 
 library stopwatch_test;
 
 import "package:expect/expect.dart";
 
@@ skipping 108 matching lines @@
     Expect.isTrue(checkTicking(sw));
     Expect.isTrue(checkStopping(sw));
     checkRestart();
     checkReset();
   }
 }
 
 main() {
   StopwatchTest.testMain();
 }