Add experimental support for disconnected layers.
Created attachment 417994 [details] Patch
Committed r271699: <https://trac.webkit.org/changeset/271699> All reviewed patches have been landed. Closing bug and clearing flags on attachment 417994 [details].
<rdar://problem/73458847>
This broke internal watchOS and tvOS builds. Removed them from the HAVE_CORE_ANIMATION_SEPARATED_LAYERS definition in https://trac.webkit.org/changeset/271722/webkit