AccessibilityARIAGridCell::parentTable() is very expensive because it repeatedly and needlessly computes accessibilityIsIgnored.
<rdar://problem/109753927>
Created attachment 466473 [details] Patch
Committed 264483@main (c9e4f6d7c684): <https://commits.webkit.org/264483@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 466473 [details].