Mark http_test as flaky, due to optimizing compiler.

pkg/pkg.status

 # Copyright (c) 2012, 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.
 
 # Don't run any test-like files that show up in packages directories. It
 # shouldn't be necessary to run "pub install" in these packages, but if you do
 # it shouldn't break the tests.
 */packages/*/*: Skip
 */*/packages/*/*: Skip
 */*/*/packages/*/*: Skip
 */*/*/*/packages/*/*: Skip
 
 # Skip non-test files ending with "_test".
 scheduled_test/lib/*: Skip
 polymer/example/scoped_style/*: Skip
 
 scheduled_test/test/scheduled_server_test: Pass, Fail # 13524
 scheduled_test/test/scheduled_process_test: Pass, Slow # Issue 9231
 
 
 # Skip test not runnable via test.dart
 third_party/html5lib/test/dom_compat_test: Skip
 third_party/html5lib/test/browser/browser_test: Skip
 
+http/test/http_test: Pass, RuntimeError # Issue 15652
+
 [ $compiler == dart2js ]
 collection_helpers/test/equality_test/01: Fail # Issue 1533
 collection_helpers/test/equality_test/02: Fail # Issue 1533
 collection_helpers/test/equality_test/03: Fail # Issue 1533
 collection_helpers/test/equality_test/04: Fail # Issue 1533
 collection_helpers/test/equality_test/05: Fail # Issue 1533
 collection_helpers/test/equality_test/none: Pass, Fail # Issue 14348
 collection_helpers/test/typed_buffers_test/01: Fail # Not supporting Int64List, Uint64List.
 
 [ $compiler == dart2js && $checked ]
@@ skipping 274 matching lines @@
 unittest/test/mock_test: StaticWarning, OK # testing unimplemented members
 
 [ $runtime == vm && ($system == windows || $system == macos) ]
 watcher/test/*/linux_test: Skip
 
 [ $runtime == vm && ($system == windows || $system == linux) ]
 watcher/test/*/mac_os_test: Skip
 
 [ $runtime == vm && $system == macos ]
 watcher/test/directory_watcher/mac_os_test: Pass, Fail # Issue 15024