Ensure window with NO_INPUT_CHANNEL drops touches

Current behaviour of the system is to drop touches when a window with
feature NO_INPUT_CHANNEL is being touched.

Whether or not this behaviour is correct, first add a test to highlight
the current behaviour.

Bug: 160305383 160425280
Test: atest inputflinger_tests:InputDispatcherMultiWindowOcclusionTests#NoInputChannelFeature_DropsTouches
Test: adb logcat | grep -i input
07-31 17:00:35.499 31208 31213 W InputDispatcher: Window without input channel will not receive the new gesture at 5781842196550
07-31 17:00:35.499 31208 31213 I InputDispatcher: Dropping event because there is no touchable window or gesture monitor at (10, 10) in display 0.

Test: atest inputflinger_tests:InputDispatcherMultiWindowOcclusionTests#NoInputChannelFeature_DropsTouchesWithValidChannel

logs:
07-31 16:58:02.692 30773 30773 E InputDispatcher: Window with input channel and NO_INPUT_CHANNEL has feature NO_INPUT_WINDOW, but a non-null token. Clearing
07-31 16:58:02.693 30773 30778 W InputDispatcher: Window with input channel and NO_INPUT_CHANNEL will not receive the new gesture at 5629036343568
07-31 16:58:02.693 30773 30778 I InputDispatcher: Dropping event because there is no touchable window or gesture monitor at (10, 10) in display 0.

Change-Id: Ied554c3a2100d74ef5fea74897301dded5dc1416