For most ProxyObject's targets this avoids costly validation logic and JS => C++ calls in the IC.
<rdar://problem/108269769>
Pull request: https://github.com/WebKit/WebKit/pull/12919
Committed 263443@main (18d9fef12db3): <https://commits.webkit.org/263443@main> Reviewed commits have been landed. Closing PR #12919 and removing active labels.
Re-opened since this is blocked by bug 256050
Pull request: https://github.com/WebKit/WebKit/pull/13349
Committed 263571@main (052608b03fab): <https://commits.webkit.org/263571@main> Reviewed commits have been landed. Closing PR #13349 and removing active labels.