QCoreApplication has a special internal mechanism to control whether
the event dispatcher should block after delivering the posted events.
To handle queued connections in nested loops properly, we should use
that functionality.
Pick-to: 5.15
Fixes: QTBUG-85981
Change-Id: I124179a23b26a995cf95ed379e97bfa62c95f42a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
fe4b246446