[llvm] [InstrRef] Preserve debug instr num in aarch64-ldst-opt. (PR #136009)

[Felipe de Azevedo Piovezan via llvm-commits]

https://github.com/felipepiovezan commented:

left some mechanical changes. I think the implementation is correct but would like to give another look once we clean up a bit

https://github.com/llvm/llvm-project/pull/136009