Revert "Revert "Put Python Dispatcher cache in dict, clear it on new registrations. (#88329)"" (#88489)
The bug was that I was accidentally caching at the wrong key name, so
we were never actually hitting the cache. I've renamed the resolved
key to final_key to avoid shadowing in this way.
This reverts commit 410ce96a23a3496a45478e0b25ffac53aa3c116f.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88489
Approved by: https://github.com/albanD
