Canvases painted into CG display list image buffers don't ever update
<rdar://problem/98798050>
Pull request: https://github.com/WebKit/WebKit/pull/8291
Committed 258586@main (7d40f6d46408): <https://commits.webkit.org/258586@main> Reviewed commits have been landed. Closing PR #8291 and removing active labels.