[Tsan] Fix the signal_errno.cc and signal_malloc.cc tests to pass on FreeBSD
Differential Revision: http://reviews.llvm.org/D5669


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@219399 91177308-0d34-0410-b5e6-96231b3b80d8