[llvm] [Attributor] Fix an issue that could potentially cause `AccessList` and `OffsetBins` out of sync (PR #106187)

[Shilei Tian via llvm-commits]

shiltian wrote:

> I don't believe the claim that llvm-reduce can't further reduce it. Can you post it

I added it in the description.

https://github.com/llvm/llvm-project/pull/106187