Support &__uuidof(type) as a non type template argument.

This idiom is used everywhere in MFC/COM code and as such this patch removes hundreds of errors when parsing MFC code with clang.

Example: 
template <class T, const GUID* g = &__uuidof(T)>
class ComTemplate  { };

typedef ComTemplate<struct_with_uuid, &__uuidof(struct_with_uuid)> COM_TYPE;

Of course this is just parsing support. Trying to use this in CodeGen will generate:
error: cannot yet mangle expression type CXXUuidofExpr

llvm-svn: 130381