Fix initial subwindow size in testcon tool
Fix initial subwindow size in testcon tool

If QAxWidget is added as a subwindow before the control is set to it,
the client area size of the subwindow will be zero, as it cannot
determine the preferred size yet.

Change-Id: Ia144aa06029dd8d949b1848a36d975a098b18113
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

kobolabs/qtactiveqt,kobolabs/qtactiveqt,xsens/qtactiveqt,xsens/qtactiveqt