tst_QMenuBar::accel() remove QApplicationPrivate::setActiveWindow()

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

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: Id53b450ea802a80715a13e4e2ae222af9101c780
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/widgets/qmenubar/tst_qmenubar.cpp

@@ -329,7 +329,6 @@ void tst_QMenuBar::accel()
     QMainWindow w;
     const TestMenu menu = initWindowWithSimpleMenuBar(w);
     w.show();
-    QApplicationPrivate::setActiveWindow(&w);
     QVERIFY(QTest::qWaitForWindowActive(&w));
     // shortcuts won't work unless the window is active
     QTest::keyClick(static_cast<QWidget *>(0), Qt::Key_A, Qt::ControlModifier );