Mark tests flaky on Safari 6.2

pkg/pkg.status

Index: pkg/pkg.status
diff --git a/pkg/pkg.status b/pkg/pkg.status
index b7f4dbeb381816ca3c5411225a904583e50e2627..2f4c7c04ff2b2ebb22c96271357b56f7b80d4c03 100644
--- a/pkg/pkg.status
+++ b/pkg/pkg.status
@@ -497,8 +497,9 @@ http/test/html/client_test: Skip # Issue 18566
 analysis_server/test/integration/search/get_type_hierarchy_test: Pass, Fail # Issue 20436
 
 [ $runtime == safari && $builder_tag == mac10_8 ]
-polymer/e2e_test/good_import/test/import_test: RuntimeError # Issue 21424
-polymer/test/custom_event_test: RuntimeError # Issue 21425
-polymer/test/instance_attrs_test: RuntimeError # Issue 21425
-polymer/test/property_observe_test: RuntimeError # Issue 21425
-intl/test/date_time_format_http_request_test: RuntimeError # Issue 21428
+polymer/test/attr_mustache_test: Pass, RuntimeError # Issue 21434
+polymer/test/auto_binding_test: Pass, RuntimeError # Issue 21434
+polymer/test/bind_test: Pass, RuntimeError # Issue 21434
+polymer/test/property_observe_test: Pass, RuntimeError # Issue 21434
+polymer/test/take_attributes_test: Pass, RuntimeError # Issue 21434
+template_binding/test/template_binding_test: Pass, RuntimeError # Issue 21434