Stabilize tst_QGraphicsItem

The cursor() test was missing a QTest::moveMouse() before sending of the
mouse event (as all the following subtests do). When run on a desktop with
the panel on the left side of the screen, the mouse pointer would land over
the left item instead of in between them, as assumed by the subtest, and
the following QCOMPARE failed.

Change-Id: Ib74fdf0cfbfbc8ecb79a906610a2da5cb50c89d0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

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

@@ -4221,6 +4221,7 @@ void tst_QGraphicsItem::cursor()
     QCursor cursor = view.viewport()->cursor();
 
     {
+        QTest::mouseMove(view.viewport(), QPoint(100, 50));
         QMouseEvent event(QEvent::MouseMove, QPoint(100, 50), Qt::NoButton, 0, 0);
         QApplication::sendEvent(view.viewport(), &event);
     }