feat(android): make scrollToTop and scrollToBottom animatable

[m1ga]

Parity for #13204

Test code

var toggle = false;
var win = Ti.UI.createWindow();
var btn = Ti.UI.createButton({
	title: "smooth scroll",
	bottom: 20,
	left: 10
});
var btn2 = Ti.UI.createButton({
	title: "normal scroll",
	bottom: 20,
	right: 10
});
var sv = Ti.UI.createScrollView({
	height: Ti.UI.FILL,
	layout:"vertical",
	contentHeight: Ti.UI.SIZE,
	scrollType: "vertical"
})
win.add([sv, btn, btn2]);
for (var i = 0; i < 50; ++i) {
	var lbl = Ti.UI.createLabel({
		text: "Label " + i,
		height: 80
	});
	sv.add(lbl);
}
btn.addEventListener("click", function() {
	if (toggle) {
		sv.scrollToTop({
			animated: true
		})
	} else {
		sv.scrollToBottom({
			animated: true
		})
	}
	toggle = !toggle;
})
btn2.addEventListener("click", function() {
	if (toggle) {
		sv.scrollToTop()
	} else {
		sv.scrollToBottom()
	}
	toggle = !toggle;
})
win.open();