Fix tst_QQuickPinchArea::cancel

The cancel event must have the device set, otherwise it may not be
delivered properly.

Change-Id: I7f7899fdbfd8fd68e9e19bcd043a46ddb31516cd
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

tests/auto/quick/qquickpincharea/tst_qquickpincharea.cpp

@@ -511,6 +511,7 @@ void tst_QQuickPinchArea::cancel()
         QCOMPARE(blackRect->scale(), 1.5);
 
         QTouchEvent cancelEvent(QEvent::TouchCancel);
+        cancelEvent.setDevice(device);
         QCoreApplication::sendEvent(window, &cancelEvent);
         QQuickTouchUtils::flush(window);