tst_QTableView::tabFocus() remove QApplicationPrivate::setActiveWindow

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

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: Id6b4fb78c8ee52a5f5eb2a9737991e7ed648f710
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/itemviews/qtableview/tst_qtableview.cpp

@@ -3829,7 +3829,6 @@ void tst_QTableView::tabFocus()
     QLineEdit *edit = new QLineEdit(&window);
 
     window.show();
-    QApplicationPrivate::setActiveWindow(&window);
     window.setFocus();
     window.activateWindow();
     QVERIFY(QTest::qWaitForWindowActive(&window));