sanitizer_common: remove SANITIZER_USE_MALLOC

It was introduced in:
9cffc955 tsan: allow to force use of __libc_malloc in sanitizer_common
and used in:
512a18e5 tsan: add standalone deadlock detector
and later used for Go support.
But now both uses are gone. Nothing defines SANITIZER_USE_MALLOC.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D114514