tests: add a shortcut to quit app in allcursors

Pick-to: 6.0 5.15
Change-Id: I6b377cacfe05fc13c9f70e37247ed4da72f3f72e
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

tests/manual/qcursor/allcursors/mainwindow.cpp

@@ -51,6 +51,9 @@ void MainWindow::keyPressEvent(QKeyEvent* event)
 {
     QPoint off(0, 0);
     switch (event->key()) {
+    case Qt::Key_Q:
+        qApp->quit();
+        break;
     case Qt::Key_Up:
         off.setY(-4);
         break;