some more tests for r179743.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179781 91177308-0d34-0410-b5e6-96231b3b80d8
[CMake] Create the directory before creating the link to the clang headers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179782 91177308-0d34-0410-b5e6-96231b3b80d8