[llvm] [Utils] update_llc_test_checks.py: updated the regexp for ARM target (PR #148287)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

This change broke `update_llc_test_checks.py` quite a few files I work on, recently:
- `llvm/test/CodeGen/AArch64/sme-za-exceptions.ll`
- and `llvm/test/CodeGen/AArch64/win-sve.ll`

But more too, I think. I was wondering what broke `update_llc_test_checks`... Please fix the AArch64 regexs or revert this change. 

https://github.com/llvm/llvm-project/pull/148287