Revert "Zone support for Futures."

tests/lib/async/catch_errors6_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:expect/expect.dart";
-import 'dart:async';
-import 'dart:isolate';
-import 'catch_errors.dart';
-
-main() {
-  // We keep a ReceivePort open until all tests are done. This way the VM will
-  // hang if the callbacks are not invoked and the test will time out.
-  var port = new ReceivePort();
-  var completer = new Completer();
-  var errorHandlerOrDoneHasBeenExecuted = false;
-  // Test that `catchErrors` doesn't shut down if a future is never completed.
-  catchErrors(() {
-    completer.future.then((x) { Expect.fail("should not be executed"); });
-  }).listen((x) {
-      errorHandlerOrDoneHasBeenExecuted = true;
-      Expect.fail("should not be executed (listen)");
-    },
-    onDone: () {
-      errorHandlerOrDoneHasBeenExecuted = true;
-      Expect.fail("should not be executed (onDone)");
-    });
-  Timer.run(() {
-    Expect.isFalse(errorHandlerOrDoneHasBeenExecuted);
-    port.close();
-  });
-}