refactor: also use emptyObject for functional listeners
refactor: also use emptyObject for functional listeners

vuejs/vue,KingMario/vue,vuejs/vue,lizhiyao/vue,Hanks10100/vue,Ddder-FE/vue,optimizely/vue,KingMario/vue,Kingwl/vue,lizhiyao/vue,Ddder-FE/vue,cnchanning/vue,Hanks10100/vue,Kingwl/vue,vuejs/vue,lizhiyao/vue,cnchanning/vue,KingMario/vue,Kingwl/vue,lizhiyao/vue,Kingwl/vue,Ddder-FE/vue,cnchanning/vue,Hanks10100/vue,Jinjiang/vue,vuejs/vue,Jinjiang/vue,Ddder-FE/vue,KingMario/vue,Jinjiang/vue,Hanks10100/vue,Jinjiang/vue