[compiler-rt] Revert "[msan] Detect dereferencing zero-alloc as use-of-uninitialized-value" (PR #156148)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

> Reverts #155944
> 
> Per post-commit discussion in [#155944 (comment)](https://github.com/llvm/llvm-project/pull/155944#discussion_r2311822441), this is detecting OOB access, which is not in scope for MSan. To be logically consistent with how MSan does not try to handle OOB in other cases, this patch reverts the MSan change. Dereferencing zero-alloc can be detected with ASan instead (as of #155943).

I am asking to make more general.

https://github.com/llvm/llvm-project/pull/156148