BELayerHierarchy should be invalidated before being deallocated.
<rdar://problem/122238284>
Pull request: https://github.com/WebKit/WebKit/pull/23810
Committed 274054@main (9f7a7a918cc5): <https://commits.webkit.org/274054@main> Reviewed commits have been landed. Closing PR #23810 and removing active labels.