QQuickWindow depends on maintaining state of known touch points
between events, so it needs to be notified when it will not be
receiving the corresponding release event for one or more.
This temporary fix needs to be reverted when we have a proper
event forwarding solution.
Task-number: QTBUG-37371
Change-Id: I5dc40af6feac425be8103c1586f8ebe3a6aad20d
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
efcfa0b252