Currently certain mutations prevent caching.
<rdar://problem/113960228>
Pull request: https://github.com/WebKit/WebKit/pull/16741
Committed 267035@main (5326da20993d): <https://commits.webkit.org/267035@main> Reviewed commits have been landed. Closing PR #16741 and removing active labels.
Re-opened since this is blocked by bug 260421