tst_QShortcut::duplicatedShortcutOverride() remove setActiveWindow()

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

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: I6ad2841a15dd9286232ad43069e3839faa3fe901
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/kernel/qshortcut/tst_qshortcut.cpp

@@ -1155,7 +1155,6 @@ void tst_QShortcut::duplicatedShortcutOverride()
     w.resize(200, 200);
     w.move(QGuiApplication::primaryScreen()->availableGeometry().center() - QPoint(100, 100));
     w.show();
-    QApplicationPrivate::setActiveWindow(&w);
     QVERIFY(QTest::qWaitForWindowActive(&w));
     QTest::keyPress(w.windowHandle(), Qt::Key_A);
     QCoreApplication::processEvents();