Make keyClick safer for QWindows going away on presses or during wait

We already have similar logic in the QWidget variant.

Pick-to: 6.3 6.2
Task-number: QTBUG-102253
Change-Id: Idf1e3474f3189909f1cba7d5dedc2cde12f1338e
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

src/testlib/qtestkeyboard.h

@@ -93,7 +93,10 @@ namespace QTest
 
 
         if (action == Click) {
+            QPointer<QWindow> ptr(window);
             sendKeyEvent(Press, window, code, text, modifier, delay);
+            if (!ptr)
+                return;
             sendKeyEvent(Release, window, code, text, modifier, delay);
             return;
         }