https://w3c.github.io/csswg-drafts/css-box-4/#margin-trim
<rdar://problem/105960289>
Pull request: https://github.com/WebKit/WebKit/pull/10731
Committed 260906@main (35416b6b8ce4): <https://commits.webkit.org/260906@main> Reviewed commits have been landed. Closing PR #10731 and removing active labels.