Resync html/cross-origin-opener-policy from upstream WPT.
Pull request: https://github.com/WebKit/WebKit/pull/4770
Committed 254939@main (a55f20a3ec08): <https://commits.webkit.org/254939@main> Reviewed commits have been landed. Closing PR #4770 and removing active labels.
<rdar://problem/100487474>