[ASan] Mark init-order test as XFAIL on Darwin

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@182365 91177308-0d34-0410-b5e6-96231b3b80d8
[nolibc] Move libc-dependent sanitizer_posix.cc code to sanitizer_posix_libcdep.cc.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@182366 91177308-0d34-0410-b5e6-96231b3b80d8