[AC-3109] Android: Hardware back-button does not function when "android:back" event listener is attached to heavyweight window

The problem

Heavyweight window can't be closed using hardware back-button when it has "android:back" event listener attached.

Test case

To see this problem run this example:

var win = Ti.UI.createWindow({
	backgroundColor: '#000'
});

var button = Ti.UI.createButton({
	title: 'Open window'
});

button.addEventListener('click', function() {
	
    var win1 = Ti.UI.createWindow({
    	title: 'Click back button',
    	modal: true,
    	backgroundColor: '#369'
    });
    
	win1.addEventListener('android:back', function() {
		Ti.API.info('Android:back');
	});
	
	win1.open();
	
});

win.add(button);

win.open();

Click on button and then try to close a window using hardware back-button. You should see that window did not close, while event has been fired as it can be seen in console output.

Expected behavior

Window needs to be closed when hardware back-button is clicked. Note that this works fine when example is compiled with 1.8.1 SDK.