Make accessibility/mac/radio-button-checkbox-size.html async-friendly so it can pass in ITM
<rdar://problem/102705353>
Created attachment 463751 [details] Patch
Committed 257076@main (f3f615111215): <https://commits.webkit.org/257076@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 463751 [details].