[llvm] [ARM] Record store with pre/post-indexed addressing as `mayStore` (PR #121565)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

Updated, thanks! That doesn't look like to be the case for ARM, as UnmodeledSideEffects (setting `hasSideEffects = 1` only) doesn't seem to imply MayStore (I'd personally set it explicitly anyways if it were the case though, for consistency).

https://github.com/llvm/llvm-project/pull/121565