tst_QAbstractItemView::setItemDelegate() remove setActiveWindow()

2f6fe3a268 has made calls to
QApplicationPrivate::setActiveWindow() redundant.

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: Ib7de6df3dc330ff8e3eff7a901eca535a4f22a2d
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/itemviews/qabstractitemview/tst_qabstractitemview.cpp

@@ -1051,7 +1051,6 @@ void tst_QAbstractItemView::setItemDelegate()
     centerOnScreen(&v);
     moveCursorAway(&v);
     v.show();
-    QApplicationPrivate::setActiveWindow(&v);
     QVERIFY(QTest::qWaitForWindowActive(&v));
 
     QModelIndex index = model.index(cellToEdit.y(), cellToEdit.x());