Revert "Zone support for Futures."

tests/lib/async/catch_errors12_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 events = [];
-  // Tests that errors that have been delayed by several milliseconds with
-  // Timers are still caught by `catchErrors`.
-  catchErrors(() {
-    events.add("catch error entry");
-    Timer.run(() { throw "timer error"; });
-    new Timer(const Duration(milliseconds: 100), () { throw "timer2 error"; });
-    new Future.value(499).then((x) {
-      new Timer(const Duration(milliseconds: 200), () { throw x; });
-    });
-    throw "catch error";
-  }).listen((x) {
-      events.add(x);
-    },
-    onDone: () {
-      Expect.listEquals([
-            "catch error entry",
-            "main exit",
-            "catch error",
-            "timer error",
-            "timer2 error",
-            499,
-          ],
-          events);
-      port.close();
-    });
-  events.add("main exit");
-}