Literals in props should not be updated

[Rich-Harris]

In a case like this...

<List items='{[1, 2, 3]}'/>

...items should never be updated, even if <List> had other properties that were being updated.

[Rich-Harris]

To clarify:

function create_main_fragment(component, ctx) {

	var list_initial_data = { items: [1, 2, 3] };
	var list = new List({
		root: component.root,
		data: list_initial_data
	});

	return {
		c: function create() {
			list._fragment.c();
		},

		m: function mount(target, anchor) {
			list._mount(target, anchor);
		},

+		p: noop,
-		p: function update(changed, ctx) {
-			var list_changes = {};
-			list_changes.items = [1, 2, 3];
-			list._set(list_changes);
-		},

		u: function unmount() {
			list._unmount();
		},

		d: function destroy() {
			list.destroy(false);
		}
	};
}