issue 847373  was filed for the virtual test version, but the default one fails too.

This test is already SLOW but has occasional timeouts:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=service-workers-force-update-on-page-load.js

Probably some race condition somewhere.

It's not clear if this is recent regression. Leaving Untriaged for now.