message: perf: deep clone slot vnodes on re-render
  avoid unnecessary assignment.
diff: @@ -95,8 +95,8 @@ export function cloneVNode (vnode: VNode, deep?: boolean): VNode {
  cloned.key = vnode.key
  cloned.isComment = vnode.isComment
  cloned.isCloned = true
  - if (deep) {
  - cloned.children = vnode.children && cloneVNodes(vnode.children)
  + if (deep && vnode.children) {
  + cloned.children = cloneVNodes(vnode.children)
  }
  return cloned
  }
  