The C++ dynamic typing tests are failing on Windows, skip for now. (#171922)
This is a follow-on to:
https://github.com/llvm/llvm-project/pull/168611
which added a bunch of tests for detecting dynamic types of C++ result
variables. I don't actually know how well dynamic type detection works
on Windows if at all. It would require Windows support, since the
Linux/Darwin version is specific to the Itanium ABI.