add 30 sec timeout to failure test

Author: srwei

infrastructure/testdriver/bidi/speculation/prefetch_status_updated.https.html

@@ -154,6 +154,6 @@
             'Should have received pending and failure events'
         );
 
-    }, "prefetch_status_updated event with prefetch failure");
+    }, "prefetch_status_updated event with prefetch failure", { timeout: 30000 });
 
 </script>