Fixed Runtime/POSIX/Isatty.c with llvm-lit (LLVM >= 3.0). Also added
CHECK-DAG lines but did not add use of FileCheck because only LLVM >=
3.4 supports CHECK-DAG directive.

This test is now broken under DejaGNU.
Fixed Runtime/POSIX/Openat.c test for llvm-lit (LLVM >= 3.0). The
test is now broken under DejaGNU.