Adjust to spec change: https://github.com/whatwg/html/pull/9439
Pull request: https://github.com/WebKit/WebKit/pull/15496
Committed 265734@main (4230d97f23d2): <https://commits.webkit.org/265734@main> Reviewed commits have been landed. Closing PR #15496 and removing active labels.
<rdar://problem/111705404>