SharedVideoFrameReader does not need to create a default IPC::Semaphore
<rdar://problem/118160442>
Pull request: https://github.com/WebKit/WebKit/pull/20226
Committed 270533@main (d891c0e48c74): <https://commits.webkit.org/270533@main> Reviewed commits have been landed. Closing PR #20226 and removing active labels.