See https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#tests=media%2Fno-fullscreen-when-hidden.html For example https://build.webkit.org/results/Apple%20iOS%2012%20Simulator%20Release%20WK2%20(Tests)/r238455%20(1119)/media/no-fullscreen-when-hidden-pretty-diff.html
Committed r238624: <https://trac.webkit.org/changeset/238624>