Make test as failing on safarimobilesim.

pkg/pkg.status

Index: pkg/pkg.status
diff --git a/pkg/pkg.status b/pkg/pkg.status
index a816a1fe579c0bf9f2833cbb1e7ef0a5deccf157..b15edca337e55e00569bba0932e7b0454576f3a3 100644
--- a/pkg/pkg.status
+++ b/pkg/pkg.status
@@ -227,6 +227,9 @@ source_maps/test/vlq_test: RuntimeError # A VLQ test checks for large numbers th
 intl/test/find_default_locale_browser_test: Fail
 intl/test/date_time_format_http_request_test: Skip # Timeout.
 
+[ $runtime == safarimobilesim ]
+polymer/test/bind_mdv_test: RuntimeError # Issue 20929
+
 [ $runtime == ie9 ]
 mime/test/mime_multipart_transformer_test: Skip # No typed_data on IE9.
 typed_data/test/typed_buffers_test: Fail, Crash # No typed_data on IE9.