fix(ssr): avoid rendering reserved internal keys in output (#5564)

fix #5563

packages/server-renderer/__tests__/ssrRenderAttrs.spec.ts

@@ -15,6 +15,8 @@ describe('ssr: renderAttrs', () => {
     expect(
       ssrRenderAttrs({
         key: 1,
+        ref_key: 'foo',
+        ref_for: 'bar',
         ref: () => {},
         onClick: () => {}
       })

packages/server-renderer/src/helpers/ssrRenderAttrs.ts

@@ -12,7 +12,7 @@ import {
 } from '@vue/shared'
 
 // leading comma for empty string ""
-const shouldIgnoreProp = makeMap(`,key,ref,innerHTML,textContent`)
+const shouldIgnoreProp = makeMap(`,key,ref,innerHTML,textContent,ref_key,ref_for`)
 
 export function ssrRenderAttrs(
   props: Record<string, unknown>,