Don't wait for asynchronous error handlers.

tests/lib/async/catch_errors15_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.
 
 import 'package:async_helper/async_helper.dart';
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'catch_errors.dart';
 
 main() {
@@ skipping 18 matching lines @@
     throw "inner throw";
   }).listen((x) {
       events.add("o $x");
     },
     onDone: () {
       Expect.listEquals(["catch error entry",
                          "catch error entry2",
                          "after inner",
                          "main exit",
                          "i catch error",
+                         // We guarantee the order of one stream but not any
+                         // global order.

[Lasse Reichstein Nielsen, 2013/09/05 09:17:25]

Why then are we testing the exact order here?
How about filtering on "i" and "o" and checking each independently?

[floitsch, 2013/09/05 09:23:08]

I could, but this was just easier.
I don't expect the actual order to change anytime soon. If it does I'm willing
to look into making it more fool-proof.

                          "o inner throw",
                          "i future error",
                          "i future error2",
                          "i 499",
                          "i delayed error",
                          "inner done",
                          ],
                          events);
       asyncEnd();
     });
   events.add("main exit");
 }