smfr did this in r211529, however this was reverted in r211559 as the iOS reftest makes it fail on macOS (and it still does on Big Sur, having just checked locally). At the very least, we should get rid of the backdrop-filter-with-clip-path-expected.txt files because they give us absolutely no coverage of what this is trying to test. But getting the reftest passing everywhere would be better!
<rdar://problem/70601321>
Created attachment 441516 [details] Patch
Created attachment 441519 [details] Patch
Comment on attachment 441519 [details] Patch rs=me
Committed r284374 (243159@main): <https://commits.webkit.org/243159@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 441519 [details].