[llvm] [ObjCARC] Change autorelease to release when the pool state is not changed between the autorelease and the pool pop (PR #152353)

[via llvm-commits]

SiliconA-Z wrote:

@rjmccall I believe I mitigated the O(n^2) performance, albiet it is gonna be hard to eliminate that complexity entirely, skipping over pools helps a lot.

https://github.com/llvm/llvm-project/pull/152353