[llvm] [ARM] Fix frame chains with M-profile PACBTI (PR #110285)

[Mark Murray via llvm-commits]

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

This looks like the code I looked at a while back, but cleaned up, and with better testing. LGTM.

https://github.com/llvm/llvm-project/pull/110285