[msan] Intercept confstr.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@187412 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Intercept pthread_join.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@187413 91177308-0d34-0410-b5e6-96231b3b80d8