[TIMOB-7499] Android: UI.View - toImage method returns transparent backgroundImage as fully opaque

Ti.UI.backgroundColor = 'yellow';
var win = Ti.UI.createWindow();

// the same issue exists when using an imageView here rather than a View
var view = Ti.UI.createView({
  backgroundColor:'transparent',
  backgroundImage: 'alpha.png',
  top: 50,
  width: 300,
  height: 300
});
win.add(view);

var blob = view.toImage();
var rendered = Ti.UI.createImageView({
  backgroundColor:'transparent',
  image: blob,
  top: 200,
  width: 300,
  height: 300
});

win.add(rendered);
win.open();