[compiler-rt] [llvm] [test][msan] Precommit tests for vararg improvements (PR #72612)

[Kirill Stoimenov via llvm-commits]

https://github.com/kstoimenov commented:

Why do we need separate ll files for ARM and X86? Is there a way to combine those? 

https://github.com/llvm/llvm-project/pull/72612