vdom.Helper: createDeltas() => separate deltas into default & remove

after adding removeAll, our result deltas filtering feels no longer reasonable:

        deltas = [
            ...deltas.filter(item => item.action !== 'removeAll' && item.action !== 'removeNode'),
            ...deltas.filter(item => item.action === 'removeAll' || item.action === 'removeNode')
        ];