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

tests/isolate/unresolved_ports_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.
 
 // spawns multiple isolates and sends unresolved ports between them.
 library unresolved_ports;
 import 'dart:async';
 import 'dart:isolate';
-import '../../pkg/unittest/lib/unittest.dart';
+import 'package:unittest/unittest.dart';
+import "remote_unittest_helper.dart";
 
 // This test does the following:
 //  - main spawns two isolates: 'tim' and 'beth'
 //  - 'tim' spawns an isolate: 'bob'
 //  - main starts a message chain:
 //       main -> beth -> tim -> bob -> main
 //    by giving 'beth' a send-port to 'tim'.
 
 bethIsolate(init) {
   ReceivePort port = initIsolate(init);
@@ skipping 45 matching lines @@
     spawnFunction(timIsolate).then((tim) {
       spawnFunction(bethIsolate).then((beth) {
         beth.send(['main says: Beth, find out if Tim is coming.',
                   tim, port.sendPort]);
       });
     });
 
   });
 }
 
-main() => baseTest();
+void main([args, port]) {
+  if (testRemote(main, port)) return;
+  baseTest();
+}