[compiler-rt] [llvm] [asan][NFCI] Rename asan_(malloc_)?linux.cpp to ...unix.cpp (PR #132263)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

If we nitpicking, Linux is not UNIX.
And there are other places when linux includes some BSD oses.

So I would not recommend incremental fixes until we have clear guideline for naming.
As-is it's rather git log noise.

https://github.com/llvm/llvm-project/pull/132263