We need to revert 258568@main since we've re-disabled form-associated custom elements in https://commits.webkit.org/258925@main
Pull request: https://github.com/WebKit/WebKit/pull/8667
Committed 258926@main (18e40f7108b3): <https://commits.webkit.org/258926@main> Reviewed commits have been landed. Closing PR #8667 and removing active labels.
<rdar://problem/104272019>
Re-opened since this is blocked by bug 250692