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

[Jessica Clarke via llvm-commits]

jrtc27 wrote:

> @jrtc27 please can you review - I think #139844 introduced the regression - should the other arm/thumb regexp be updated similarly?

I assume so. Currently travelling but will take a look when I can this week. I think I copied this from another target’s but it’s possible I had to edit it and botched that.

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