[Sanitizers] ASan and LSan allocator set errno on failure.

Summary:
Set proper errno code on alloction failures and change some
implementations to satisfy their man-specified requirements:

LSan: valloc and memalign
ASan: pvalloc, memalign and posix_memalign

Changing both allocators in one patch since LSan depends on ASan allocator in some configurations.

Reviewers: vitalybuka

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D35440

llvm-svn: 308064