LayoutTest fast/events/before-unload-returnValue.html is a flaky failure (reporting FailureNotTested) https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#tests=fast%2Fevents%2Fbefore-unload-returnValue.html See these EWS false positives: https://bugs.webkit.org/buglist.cgi?quicksearch=fast%2Fevents%2Fbefore-unload-returnValue.html&list_id=2771558
Skipped test in https://trac.webkit.org/changeset/217514/webkit
*** Bug 172616 has been marked as a duplicate of this bug. ***
It appears that this flaky 'missing result' is also happening on macOS testers.