tst_QTooltip::keyEvent() remove QApplicationPrivate::setActiveWindow()

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

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: I7f87b71237f679575a093ac5d28ddd2c9a911492
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/kernel/qtooltip/tst_qtooltip.cpp

@@ -98,7 +98,6 @@ void tst_QToolTip::keyEvent()
     widget.setWindowTitle(QLatin1String(QTest::currentTestFunction())
                           + QLatin1Char(' ') + QLatin1String(QTest::currentDataTag()));
     widget.show();
-    QApplicationPrivate::setActiveWindow(&widget);
     QVERIFY(QTest::qWaitForWindowActive(&widget));
 
     widget.showDelayedToolTip(100);