[MSan] Switch to common aligned allocs tests.

Summary:
Switch to aligned_alloc and posix_memalign tests in sanitizer_common
and delete the MSan-specific ones.

Reviewers: vitalybuka

Subscribers: srhines, kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D47968

llvm-svn: 334340