tsan: add interface functions for unaligned access, e.g. __sanitizer_unaligned_load16


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@180780 91177308-0d34-0410-b5e6-96231b3b80d8
tsan: reverse stack trace for failed CHECK's, this is how we print traces in other places


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@180781 91177308-0d34-0410-b5e6-96231b3b80d8