[llvm] LAA: thoroughly clarify stride-versioning code (NFC) (PR #97075)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

Thanks to the comprehensive testing that was recently landed, we now know that the existing code is correct, and cannot be improved. The patch has now been converted into an NFC.

https://github.com/llvm/llvm-project/pull/97075