Windows/ActiveQt: Pass native parent handle property from widget to widget window.

Task-number: QTBUG-31672
Task-number: QTBUG-32343

Change-Id: I6b1eca13248da06db739b1a8356a0259f7f4ae6c
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>