Clean up a bit of the type getting code where lldb_private:Type now has

    clang_type_t
    GetClangFullType(); // Get a completely defined clang type

    clang_type_t
    GetClangLayoutType(); // Get a clang type that can be used for type layout
    
    clang_type_t
    GetClangForwardType(); // A type that can be completed if needed, but is more efficient.
    

llvm-svn: 125691