[web-animations] accelerated animations should not run accelerated
<rdar://problem/88756985>
Created attachment 451549 [details] Patch
Committed r289598 (247111@main): <https://commits.webkit.org/247111@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 451549 [details].
Committed r289605 (247118@trunk): <https://commits.webkit.org/247118@trunk>