QDialog today only hides itself during reject and accept, it doesn't
close itself properly. This is problematic, as it doesn't close the
QWindow.
However, fixing this behavior must not result in duplicate calls to
virtual function, or additional calls to virtual functions (such as
closeEvent) without explicitly flagging the change in the changelog.
Add more tests to document existing behavior so that we can identify
such changes and verify the desired side effects.
Pick-to: 6.2
Change-Id: I1f30701cd766eb3c7957751b51e8579d4542dd16
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
d2cad026c7