When mixing native and regular widgets in same QMdiArea, some
subwindows didn't properly get set native. This was because
when a native parentless widget was given a parent, it wouldn't
enforce native window on the new parent and its ancestors.
This happened because window flags were adjusted too late in
relation to createWinId() call in setParent_sys().
Fixed by moving the createWinId() call to its proper place.
Also removed some old Q_WS_* ifdeffing in QWidget::setParent() that
masked some native enforcement code.
Additionally removed few QEXPECT_FAILs from QWidget autotest now
that those cases work correctly.
Task-number: QTBUG-26424
Change-Id: Ib6f9d0531e5c7299e2c307734d49c81f1ffa9713
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>
150284198b