feat: update Suspense usage (#2099)

See https://github.com/vuejs/vue-next/pull/2099 for details.

packages/runtime-core/src/index.ts

@@ -250,7 +250,6 @@ import {
   setCurrentRenderingInstance
 } from './componentRenderUtils'
 import { isVNode, normalizeVNode } from './vnode'
-import { normalizeSuspenseChildren } from './components/Suspense'
 
 const _ssrUtils = {
   createComponentInstance,
@@ -258,8 +257,7 @@ const _ssrUtils = {
   renderComponentRoot,
   setCurrentRenderingInstance,
   isVNode,
-  normalizeVNode,
-  normalizeSuspenseChildren
+  normalizeVNode
 }
 
 /**