fixes to polymer, gets tests back to a stable state

pkg/polymer/test/attr_mustache_test.dart

Index: pkg/polymer/test/attr_mustache_test.dart
diff --git a/pkg/polymer/test/attr_mustache_test.dart b/pkg/polymer/test/attr_mustache_test.dart
index 50753b30c368ed4d5547eb51c1fcbab1b3224549..1186b9329c37634f5ef9c7872a6afdd6d53ddaa7 100644
--- a/pkg/polymer/test/attr_mustache_test.dart
+++ b/pkg/polymer/test/attr_mustache_test.dart
@@ -46,6 +46,8 @@ class XTest extends PolymerElement {
 @initMethod _main() {
   useHtmlConfiguration();
 
+  setUp(() => Polymer.onReady);
+
   test('mustache attributes', () {
     final xtest = document.query('#test').xtag;
     final xtarget = xtest.shadowRoot.query('#target').xtag;