webanimations/accelerated-animation-slot-invalidation.html is frequently failing on Windows EWS bots It doesn't appear to be failing on post-commit bots, though: https://results.webkit.org/?suite=layout-tests&test=webanimations%2Faccelerated-animation-slot-invalidation.html&version_name=Win10
Created attachment 399283 [details] actual image
Created attachment 399284 [details] expected image
The attached images show a smaller than expected purple square being displayed https://ews-build.webkit.org/results/Windows-EWS/r399134-17929/webanimations/accelerated-animation-slot-invalidation-diffs.html
<rdar://problem/63192835>
Marked the test as flaky in https://trac.webkit.org/changeset/261631 to speed up EWS.