Port IPC::SharedBufferReference to the new IPC serialization format.
Pull request: https://github.com/WebKit/WebKit/pull/20614
Committed 270893@main (e3633fb4dca3): <https://commits.webkit.org/270893@main> Reviewed commits have been landed. Closing PR #20614 and removing active labels.
<rdar://problem/118567796>