[mer]: Fix race condition when delivering touch events. Contributes t…

…o JB#37369.

'lastPoints' is used outside the mutex locked section, so
it naturally cannot be a const &. QVector copy-on-write will
now make this access safe across receiver and delivery thread.

src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp

@@ -890,7 +890,7 @@ void QEvdevTouchScreenHandlerThread::filterAndSendTouchPoints()
     }
 
     QList<QWindowSystemInterface::TouchPoint> points = m_handler->d->m_touchPoints;
-    const QList<QWindowSystemInterface::TouchPoint> &lastPoints = m_handler->d->m_lastTouchPoints;
+    QList<QWindowSystemInterface::TouchPoint> lastPoints = m_handler->d->m_lastTouchPoints;
 
     m_handler->d->m_mutex.unlock();