QDialog::setVisible() tries to adjusts the dialog position, but
it's not really possible if the dialog size is not defined yet.
Besides, if the dialog window is not created, QWidget::move()
will not really move it and will set WA_PendingMoveEvent flag.
And QWidget::setVisible() also will not change the position,
because we reset WA_Moved flag. Thus it may break adjusting
the position in QDialog::showEvent().
So adjust the position only in QDialog::showEvent().
Task-number: QTBUG-36185
Task-number: QTBUG-39259
Task-number: QTBUG-41844
Change-Id: I015a19f2e533f68178f4ee7519b17f5e9b5def7b
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>
6468cf4e79