Implement Temporal.PlainDate[Time].{equals, add, subtract}
Pull request: https://github.com/WebKit/WebKit/pull/4215
Committed 254366@main (d4d2f95f4081): <https://commits.webkit.org/254366@main> Reviewed commits have been landed. Closing PR #4215 and removing active labels.
<rdar://problem/99803697>
Re-opened since this is blocked by bug 245075