Reenable polymer_expressions syntax_test.

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/lib/*: Skip
 polymer/example/*: Skip
 
 scheduled_test/test/scheduled_server_test: Pass, Fail, Slow, Crash # Issue 9231, 9582
 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
 
-polymer_expressions/test/syntax_test: Skip # Issue 12954
-
 [ $compiler == dart2js && $runtime == d8 ]
 unmodifiable_collection/test/unmodifiable_collection_test: Pass, Fail # Issue 12429
 
 [ $compiler == dart2js ]
 analyzer_experimental/test/generated/ast_test: Fail #Issue 12341
 
 [ $compiler == dart2js && $checked && $runtime == ie9 ]
 crypto/test/base64_test: Timeout # Issue 12486
 
 [ $compiler == dart2js && $runtime == drt ]
@@ skipping 167 matching lines @@
 mutation_observer: Skip
 polymer_expressions/test/syntax_test: Skip
 third_party/html5lib/test/browser/browser_test: Skip
 
 [ $runtime == safari || $runtime == chrome || $runtime == ie9 || $runtime == ff || $runtime == dartium || $runtime == drt ]
 docgen/test/single_library_test: Skip # Uses dart:io
 
 # Issue http://dartbug.com/12930
 [ $runtime == vm ]
 intl/test/message_extraction/message_extraction_test: Pass, Fail # Issue 12930