QFutureInterface setProgressValue allows to set values outside of progress range

Current QFutureInterface progress functionality supports setting a value out of range:

QFutureInterface<int> iface;
iface.setProgressRange(0, 2);
iface.setProgressValue(10);  // outside of [0, 2] range
iface.progressValue();  // returns 10

This didn't affect us so far due to QFutureInterface being an "internal" public class. With QPromise being introduced, this would be a visible public functionality.