Per steps 5-6 of https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver.
Pull request: https://github.com/WebKit/WebKit/pull/9867
Committed 260077@main (0676bad565ab): <https://commits.webkit.org/260077@main> Reviewed commits have been landed. Closing PR #9867 and removing active labels.
<rdar://problem/105234058>