imported/w3c/web-platform-tests/html/semantics/forms/textfieldselection/selection-start-end.html [ Crash ] media/video-multiple-concurrent-playback.html [ Crash ]
I don't think media/video-multiple-concurrent-playback.html is concerned by this issue, actually it's passing since r226948 according https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=media%2Fvideo-multiple-concurrent-playback.html
The test(s) filed under this bug have been consistently passing for the last 4000 revisions. Marking bug as fixed. Committed r263254: <https://trac.webkit.org/changeset/263254>