Tests are failing. I'll regroup and see if my EXTENDED_ARG handling is at fault or if it was pre-existing, and then proceed from there. For now, this is another Draft PR, and I'll isolate my test cleanups in a new PR.

UPDATE: Fixed by gh-106492, rebased, undrafted.

I get the same failure with just Fix and clean up uops and executor API. That makes me think the root problem is pre-existing (since that commit has no C code). I'll see if the address sanitizer will help me debug this.

UPDATE: Yeah, the UOpOptimizer type was missing a tp_dealloc handler. Nasty. Fixing that in gh-106492. Once that's merged I'll rebase and undraft this.