[llvm] [CodeGen] Combine two loops in SloIndexes.cpp file (PR #127631)

[via llvm-commits]

Rifet-c wrote:

Hi @arsenm, this is my first time contributing to LLVM and therefore I am wondering, is it ok that all the checks are passed, but no reviewers are assigned?
Also, may I ask you to review this patch or redirect it to some other person, if that's not your part of LLVM to maintain?
Many thanks!

https://github.com/llvm/llvm-project/pull/127631