[llvm] [ARM] Fix CMSE S->NS calls when CONTROL_S.SFPA==0 (CVE-2024-7883) (PR #114433)

[Oliver Stannard via llvm-commits]

ostannard wrote:

That test failed on an expensive-checks buildbot, so I've reverted it for now: https://lab.llvm.org/buildbot/#/builders/16/builds/8346

The error message points to the argument saving instructions at the start of the call sequence, not the new `vmov` added by this change, so it's probably a pre-existing bug.

https://github.com/llvm/llvm-project/pull/114433