Enable site isolation in NavigatingCrossOriginIframeToSameOrigin and fix failures which happen after enabling
Pull request: https://github.com/WebKit/WebKit/pull/13466
Committed 263747@main (4ca041a13dfa): <https://commits.webkit.org/263747@main> Reviewed commits have been landed. Closing PR #13466 and removing active labels.
<rdar://problem/108979972>