Fix TestPaths.py on windows

I committed an implementation of GetClangResourceDir on windows but
forgot to update this test. I merged the tests like I intended to, but I
realized that the test was actually failing. After looking into it, it
appears that FileSystem::Resolve was taking the path and setting
the FileSpec's Directory to "/path/to/lldb/lib/clang/" and the File to
"9.0.0" which isn't what we want. So I removed the resolve line from
DefaultComputeClangResourceDir.

llvm-svn: 355648