[WebCodecs] H264AnnexBBufferToCMSampleBuffer is not always computing the right AVC buffer size
<rdar://problem/101593041>
Pull request: https://github.com/WebKit/WebKit/pull/5817
Committed 256059@main (d3026305f6a9): <https://commits.webkit.org/256059@main> Reviewed commits have been landed. Closing PR #5817 and removing active labels.