[libc][nacl-ported-tests] Also check for hwasan in TestPosixMemAlign

An alignment failure is expected for this test when calling
posix_memalign. This is normally caught in asan, but hwasan also catches
this, so we should ignore this for hwasan as well.

Change-Id: I75537b50560364d74aa2c0d03e7c84ff1c14c6c7
Reviewed-on: https://fuchsia-review.googlesource.com/c/libc-tests/+/1069481
Commit-Queue: Leonard Chan <leonardchan@google.com>
Reviewed-by: Roland McGrath <mcgrathr@google.com>