Add logging to help diagnose issues with RemoteLayerBackingStore buffer swapping.
<rdar://problem/106875525>
Pull request: https://github.com/WebKit/WebKit/pull/11665
Committed 261822@main (a73d5e722266): <https://commits.webkit.org/261822@main> Reviewed commits have been landed. Closing PR #11665 and removing active labels.