r95912, r95914, r95917 made several tests crash on the Qt bot. I don't know how many, because tests are stopped because of too many test crash. And unfortunately 4 tests crash a previous bug: https://bugs.webkit.org/show_bug.cgi?id=68780 I tried to revert this trio locally and then only the previous 4 tests crash.
It made 375 tests crash on Qt-ARM platform and 13 tests on Qt 32-bit release.
Do you have symbol-rich backtraces for these crashes?
Can you post a link to a builder?
It seems your last patch fixed these crashes. *** This bug has been marked as a duplicate of bug 68860 ***