Fix test for multiscreen

QTBUG_7714_fullUpdateDiscardingOpacityUpdate2() would fail when
it moved to another screen if there is one to the left.

Change-Id: I3f8edc04c31dffc5a3bd005d9e5170dd68151df7
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

tests/auto/widgets/graphicsview/qgraphicsitem/tst_qgraphicsitem.cpp

@@ -11348,7 +11348,7 @@ void tst_QGraphicsItem::QTBUG_7714_fullUpdateDiscardingOpacityUpdate2()
 
     origView.show();
     QVERIFY(QTest::qWaitForWindowActive(&origView));
-    origView.setGeometry(origView.width() + 20, 20,
+    origView.setGeometry(origView.x() + origView.width() + 20, origView.y() + 20,
                          origView.width(), origView.height());
 
     parentGreen->setFlag(QGraphicsItem::ItemIgnoresTransformations);