[sanitizer] Intercept pthread_attr_get*.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@193405 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Zerofill initstate_r buffer in random_r test.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@193406 91177308-0d34-0410-b5e6-96231b3b80d8