Allow Observatory debugger to switch isolates.

runtime/observatory/test/isolate_lifecycle_test.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 import 'dart:isolate' as I;
 import 'dart:math';
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 49 matching lines @@
         resumedReceived++;
         if (resumedReceived == resumeCount) {
           sub.cancel();
           completer.complete(null);
         }
       }
     });
     var resumesIssued = 0;
     var isolateList = vm.isolates.toList();
     for (var isolate in isolateList) {
-      if (isolate.name == 'root') {
+      if (isolate.name.endsWith('main')) {
         continue;
       }
       try {
         resumesIssued++;
         await isolate.resume();
       } catch(_) {}
       if (resumesIssued == resumeCount) {
         break;
       }
     }
@@ skipping 11 matching lines @@
     }
     expect(pausedCount, spawnCount - resumeCount);
     expect(runningCount, 1);
   },
 ];
 
 main(args) async => runVMTests(args, tests,
                                testeeBefore: before,
                                testeeConcurrent: during,
                                pause_on_exit: true);