perf: deep clone slot vnodes on re-render (#6478)
perf: deep clone slot vnodes on re-render (#6478)

avoid unnecessary assignment.
lizhiyao/vue,Ddder-FE/vue,optimizely/vue,KingMario/vue,lizhiyao/vue,vuejs/vue,Jinjiang/vue,Kingwl/vue,vuejs/vue,Jinjiang/vue,cnchanning/vue,Hanks10100/vue,KingMario/vue,Ddder-FE/vue,vuejs/vue,Hanks10100/vue,Kingwl/vue,Hanks10100/vue,cnchanning/vue,Hanks10100/vue,Jinjiang/vue,KingMario/vue,vuejs/vue,lizhiyao/vue,Ddder-FE/vue,Kingwl/vue,Kingwl/vue,lizhiyao/vue,Ddder-FE/vue,cnchanning/vue,Jinjiang/vue,KingMario/vue