Revert "Reapply zone tasks."

tests/html/html.status

 # 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.
 
 interactive_test: Skip # Must be run manually.
 cross_frame_test: Skip # Test reloads itself. Issue 18558
 
 [ $compiler == none && ($runtime == dartium || $runtime == drt) ]
 
 mirrors_js_typed_interop_test: Fail # Missing expected failure (Issue 25044)
@@ skipping 124 matching lines @@
 scripts_htmltest: Skip # Times out on IE.  Issue 21537
 two_scripts_htmltest: Skip # Times out on IE.  Issue 21537
 deferred_multi_app_htmltest: Skip # Times out on IE.  Issue 21537
 localstorage_test: Pass, RuntimeError # Issue 22166
 storage_test: Pass, RuntimeError # Issue 22166
 postmessage_structured_test/more_primitives: Fail # Does not support the MessageEvent constructor.
 notification_test/supported_notification: Fail # Notification not supported on IE
 event_test: RuntimeError # Issue 23437. Only three failures, but hard to break them out.
 wheelevent_test: RuntimeError # Issue 23437
 text_event_test: RuntimeError # Issue 23437
-event_zone_task_test: RuntimeError # Issue 23437
 transition_event_test/functional: Skip # Times out. Issue 22167
 request_animation_frame_test: Skip # Times out. Issue 22167
 
 [$runtime == ie10 ]
 # IE10 Feature support statuses-
 # All changes should be accompanied by platform support annotation changes.
 audiobuffersourcenode_test/supported: Fail
 audiocontext_test/supported: Fail
 crypto_test/supported: Fail
 css_test/supportsPointConversions: Fail
@@ skipping 199 matching lines @@
 
 [ $compiler == dart2js &&  ($runtime == chrome || $runtime == drt) ]
 svgelement_test/supported_altGlyph: RuntimeError # Issue 25787
 
 [ ($runtime == dartium) && ($system == macos || $system == windows || $system == linux)]
 # Desktop operating systems do not support touch events on chrome 34 dartium.
 touchevent_test/supported: Fail
 
 [ (($runtime == dartium || $runtime == drt) && $system == macos) || $system == windows ]
 xhr_test/xhr: Skip # Times out.  Issue 21527
-xhr_task_test/xhr: Skip # Times out.  Issue 21527
 
 [ $compiler == dart2analyzer ]
 custom/document_register_basic_test: StaticWarning
 custom/element_upgrade_test: StaticWarning
 datalistelement_test: StaticWarning
 documentfragment_test: StaticWarning
 element_add_test: StaticWarning
 element_test: StaticWarning
 events_test: StaticWarning
 htmlelement_test: StaticWarning
@@ skipping 17 matching lines @@
 # These are raw dart:js tests that fail due to bugs in the CPS IR:
 js_test/Dart_functions: RuntimeError # Tree-shaking an escaping closure #25720
 
 [ $compiler == dart2js && $cps_ir && $host_checked ]
 js_typed_interop_default_arg_test/none: Crash # Issue 25911
 js_typed_interop_default_arg_test/default_value: Crash # Issue 25911
 js_typed_interop_default_arg_test/explicit_argument: Crash # Issue 25911
 
 [ $compiler == dart2js && $cps_ir && $checked ]
 *: Skip # `assert` not implemented