Add NetBSD support in sanitizer_test_utils.h

Summary:
NetBSD ships with printf_l(3) like FreeBSD.

NetBSD does not ship with memalign, pvalloc, malloc with "usable size"
and is the same here as Darwin, Android, FreeBSD and Windows.

Sponsored by <The NetBSD Foundation>

Reviewers: joerg, vitalybuka, kcc, fjricci, filcab

Reviewed By: vitalybuka

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

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D36373

llvm-svn: 310248