Mark pkg/stack_trace/test/chain_test as timing out on browsers.

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
@@ skipping 173 matching lines @@
 
 [ $compiler == dart2js && $minified ]
 # The unminified unittest tests test that the real names of Dart types are
 # printed. Minified versions of these tests exist that test the behavior when
 # minified.
 matcher/test/*_unminified_test: Skip # DO NOT COPY THIS UNLESS YOU WORK ON DART2JS
 matcher/test/mirror_matchers_test: Fail # Issue 15405
 
 [ $compiler == dart2js && $browser ]
 stack_trace/test/vm_test: Fail, OK # VM-specific traces
-stack_trace/test/chain_test: Fail # Issues 15171 and 15105
+stack_trace/test/chain_test: Fail, Timeout # Issues 15171, 15105, and 18142
 crypto/test/sha256_test: Slow, Pass
 crypto/test/sha1_test: Slow, Pass
 polymer/example/component: Fail # Issue 13198
 polymer/test/mirror_loader_test: Skip # tests development only behavior
 
 [ $compiler == dart2js && $runtime == chromeOnAndroid ]
 docgen/test/single_library_test: Fail # TODO(kasperl): Please triage.
 intl/test/date_time_format_http_request_test: Fail # TODO(kasperl): Please triage.
 
 [ $browser ]
@@ skipping 152 matching lines @@
 third_party/angular_tests/browser_test/core/scope: Skip # Requires checked mode.
 third_party/angular_tests/browser_test/core/zone: Skip # Requires checked mode.
 third_party/angular_tests/browser_test/directive/ng_repeat: Skip # Issue 17152
 third_party/angular_tests/browser_test/change_detection/dirty_checking_change_detector: Skip # Issue 17152
 
 [ $use_repository_packages ]
 analyzer/test/*: PubGetError
 
 [ $runtime == ie9 ]
 polymer: Pass, Fail, Timeout # Issue 16717