Implement on stack replacement for the in place interpreter, allowing tier up to both BBQ and OMG. JS2 scores are very similar to LLInt, at roughly 330.
<rdar://problem/113768807>
Pull request: https://github.com/WebKit/WebKit/pull/16617
Committed 266887@main (5f18ff5fc08d): <https://commits.webkit.org/266887@main> Reviewed commits have been landed. Closing PR #16617 and removing active labels.