Release 0.12.0-beta.0.

This is a beta release since all of the major foundational work is now
in place.

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1039033002
diff --git a/pubspec.yaml b/pubspec.yaml
index 35be328..be020bf 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: unittest
-version: 0.12.0-alpha.1
+version: 0.12.0-beta.0
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/unittest
diff --git a/test/util/string_literal_iterator_test.dart b/test/util/string_literal_iterator_test.dart
index bd4b56e..e16f6ba 100644
--- a/test/util/string_literal_iterator_test.dart
+++ b/test/util/string_literal_iterator_test.dart
@@ -2,6 +2,8 @@
 // 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.
 
+@TestOn("vm")
+
 import 'package:analyzer/analyzer.dart';
 import 'package:unittest/unittest.dart';
 import 'package:unittest/src/util/string_literal_iterator.dart';