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

tests/standalone/src/FileOutputStreamTest.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.
 // Testing file input stream, VM-only, standalone test.
 
 #import("dart:io");
+#import("dart:isolate");
 
 void testOpenOutputStreamSync() {
   Directory tempDirectory = new Directory('');
 
   // Create a port for waiting on the final result of this test.
   ReceivePort done = new ReceivePort();
   done.receive((message, replyTo) {
     tempDirectory.deleteSync();
     done.close();
   });
@@ skipping 89 matching lines @@
     };
   };
 }
 
 
 main() {
   testOpenOutputStreamSync();
   testOpenOutputStreamAsync();
   testOutputStreamNoPendingWrite();
 }