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

tests/standalone/src/FileTest.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 file I/O.
 
 #import("dart:io");
+#import("dart:isolate");
 
 class MyListOfOneElement implements List {
   int _value;
   MyListOfOneElement(this._value);
   int get length() => 1;
   operator [](int index) => _value;
 }
 
 class FileTest {
   static Directory tempDirectory;
@@ skipping 1087 matching lines @@
       testWriteVariousLists();
       testDirectory();
       testDirectorySync();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }