[Sanitizer] extend internal libc with stat/fstat/lstat functions

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@174316 91177308-0d34-0410-b5e6-96231b3b80d8
[Sanitizer] use proper casting in *stat functions on Mac

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@174318 91177308-0d34-0410-b5e6-96231b3b80d8
asan/tsan: fix failing CHECK on windows


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@174319 91177308-0d34-0410-b5e6-96231b3b80d8