[llvm] [ARM] Add basic NPM support for LoadStoreOptimizer (PR #184139)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM. Is this just drive-by work on NPM for ARM/AArch64, or is there a more concrete plan for this work?

https://github.com/llvm/llvm-project/pull/184139