Bug 258868 introduced a baseline computation for wide-layout attachments. Unfortunately it can drift at every layout, I'm assuming because the `renderRect`s rely on the baseline, which then gets modified, changing the next `renderRect`a.
<rdar://problem/111991128>
Pull request: https://github.com/WebKit/WebKit/pull/15680
Committed 265894@main (28021b9b53fe): <https://commits.webkit.org/265894@main> Reviewed commits have been landed. Closing PR #15680 and removing active labels.