Make isolate tests work on drt (and hopefully dartium).

tests/isolate/count_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.
 
 library CountTest;
-import '../../pkg/unittest/lib/unittest.dart';
 import 'dart:isolate';
+import 'package:unittest/unittest.dart';
+import "remote_unittest_helper.dart";
 
 void countMessages(replyTo) {
   int count = 0;
   var port = new ReceivePort();
   replyTo.send(["init", port.sendPort]);
   port.listen((int message) {
     if (message == -1) {
       expect(count, 10);
       replyTo.send(["done"]);
       port.close();
       return;
     }
     count++;
     expect(message, count);
     replyTo.send(["count", message * 2]);
   });
 }
 
-void main() {
+void main([args, port]) {
+  if (testRemote(main, port)) return;
   test("count 10 consecutive messages", () {
     ReceivePort local = new ReceivePort();
     Isolate.spawn(countMessages, local.sendPort);
     SendPort remote;
     int count = 0;
     var done = expectAsync0((){});
     local.listen((msg) {
       switch (msg[0]) {
         case "init":
           expect(remote, null);
@@ skipping 12 matching lines @@
           expect(count, 10);
           local.close();
           done();
           break;
         default:
           fail("unreachable: ${msg[0]}");
       }
     });
   });
 }