Return early in theme painting on macOS if GPU is not available, since we will crash when falling back to OpenGL otherwise.
<rdar://problem/100386989>
Pull request: https://github.com/WebKit/WebKit/pull/6003
Committed 256539@main (829dab614cc1): <https://commits.webkit.org/256539@main> Reviewed commits have been landed. Closing PR #6003 and removing active labels.
*** Bug 247860 has been marked as a duplicate of this bug. ***