isolates refactor: this change introduces 'dart:isolate' as a library. This is a

tests/isolate/src/MandelIsolateTest.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("MandelIsolateTest");
+#library('MandelIsolateTest');
+#import('dart:isolate');
 #import('TestFramework.dart');
 
 final TERMINATION_MESSAGE = -1;
 final N = 100;
 final ISOLATES = 20;
 
 void test(TestExpectation expect) {
   final state = new MandelbrotState();
   expect.completes(state._validated.future).then((result) {
     Expect.isTrue(result);
@@ skipping 130 matching lines @@
       result[x] = i;
     }
     return result;
   }
 
 }
 
 main() {
   runTests([test]);
 }