- Add code for destroying the thread-local storage data, but don't use
  it yet.
- Don't release apartment on changing modes because we didn't add a
  reference anywhere.
- Quieten the RPC_E_DISCONNECTED error message as it is an expected
  return code.
- Treat IID_NULL the same as IID_IUnknown.
- Make tests compile on Win95 again.
- Fix copy+paste error where the test failure should be from the
  CoUnmarshalInterface function.