Replace USE(MTLSHAREDEVENT_FOR_MTLTEXTURE_FOR_XR_LAYER_DATA) and USE(MTLTEXTURE_FOR_XR_LAYER_DATA) with PLATFORM(COCOA).
<rdar://problem/114428976>
Pull request: https://github.com/WebKit/WebKit/pull/17052
Committed 267338@main (ee8d9ff29a5c): <https://commits.webkit.org/267338@main> Reviewed commits have been landed. Closing PR #17052 and removing active labels.