[compiler-rt] [sanitizer_common] Implement address sanitizer on AIX: process memory mapping (PR #138537)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

> LGTM, but I didn't look into AIX specifics
> 
> Please (7/n) -> issue #

Done for this one.
Is it OK?

https://github.com/llvm/llvm-project/pull/138537