Add a VM page to the observatory.

tests/standalone/vmservice/multiple_isolate_list_test.dart

 // Copyright (c) 2013, 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 multiple_isolate_list_test;
 
 import 'test_helper.dart';
 import 'package:expect/expect.dart';
 
 class MultipleIsolateListTest extends VmServiceRequestHelper {
-  MultipleIsolateListTest(port) : super('http://127.0.0.1:$port/isolates');
+  MultipleIsolateListTest(port) : super('http://127.0.0.1:$port/vm');
 
   onRequestCompleted(Map reply) {
-    IsolateListTester tester = new IsolateListTester(reply);
+    VMTester tester = new VMTester(reply);
     tester.checkIsolateCount(2);
   }
 }
 
 main() {
   var process = new TestLauncher('multiple_isolate_list_script.dart');
   process.launch().then((port) {
     var test = new MultipleIsolateListTest(port);
     test.makeRequest().then((_) {
       process.requestExit();
     });
   });
 }