Fix ddc async test code

pkg/dev_compiler/tool/run.js

 // Copyright (c) 2016, 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.
 
 /// This is a utility to run and debug an individual DDC compiled test.
 /// Tests can be run with either node or devtool (a Chrome-based utility with
 /// DOM APIs and developer tools support).
 ///
 /// Install devtool via:
 /// > npm install -g devtool
@@ skipping 36 matching lines @@
 function finish(e) {
   if (e) {
     console.log('Test ' + test + ' failed:\n' + e.toString());
     sdk.dart.stackPrint(e);
   } else {
     console.log('Test ' + test + ' passed.');
   }
 }
 
 var async_helper = requirejs('async_helper').async_helper;
+sdk._isolate_helper.startRootIsolate(() => {}, []);
 async_helper.asyncTestInitialize(finish);
 
 var module = requirejs(test);
 var lib = test.split('/').slice(-1)[0];
 try {
-  var result = sdk._isolate_helper.startRootIsolate(module[lib].main, []);
+  var result = module[lib].main();
   // async_helper tests call finish directly - call here for all other
   // tests.
   if (!async_helper.asyncTestStarted) {
-    if (!result || !(result instanceof dart_sdk.async.Future)) {
+    if (!result || !(sdk.async.Future.is(result))) {
       finish();
     } else {
       // Wait iff result is a future
-      result.then(dart_sdk.dart.dynamic)(() => finish());
+      result.then(sdk.dart.dynamic)(() => finish(), { onError: (e) => finish(e) });
     }
   }
 } catch (e) {
   finish(e);
 }