[sanitizer][mips] Fix the condition to include sanitizer_atomic_clang_mips.h

The Glibc header [1] define _ABIO32 unconditionally on MIPS.  So we need
to compare _MIPS_SIM and _ABIO32 to know if we are actually building for
MIPS32.  Using sanitizer_atomic_clang_mips.h can cause test failures and
hangs on MIPS64.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/mips/sgidefs.h

Reviewed By: dvyukov, vitalybuka, MaskRay

Differential Revision: https://reviews.llvm.org/D121207