html_escape_test does not fail with the dart sdk the build bot uses.

test/browser/language_tests.js

 // Copyright (c) 2015, 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.
 
 (function() {
   'use strict';
 
   let dart_sdk = dart_library.import('dart_sdk');
   dart_sdk._isolate_helper.startRootIsolate(function() {}, []);
   let async_helper = dart_library.import('async_helper').async_helper;
@@ skipping 456 matching lines @@
       // you increase the time by a large amount, but it's pretty gratuitous.
       // I'm not sure why they are so slow. One guess is that they are spewing
       // a ton of warnings, that slow down the test.
       'chunked_conversion_utf84_test': skip_timeout,
       'chunked_conversion_utf88_test': skip_timeout,
       'chunked_conversion_utf8_test': skip_timeout,
 
       // TODO(rnystrom): Strong mode cast failures.
       'codec1_test': fail,
       'encoding_test': skip_timeout,
-      'html_escape_test': fail,
 
       // TODO(rnystrom): If this test is enabled, karma gets confused and
       // disconnects randomly.
       'json_lib_test': skip_fail,
 
       'json_utf8_chunk_test': skip_timeout,
 
       // TODO(rnystrom): Strong mode cast failure.
       'line_splitter_test': fail,
 
@@ skipping 331 matching lines @@
 
     for (let action of unittest_tests) {
       try {
         action();
       } catch (e) {
         console.error("Caught error tying to setup test:", e);
       }
     }
   });
 })();