chore(compiler-sfc): remove unused variable (vuejs#12750)

Author: jh-leong

packages/compiler-sfc/src/compileScript.ts

@@ -170,8 +170,6 @@ export function compileScript(
   const scriptLang = script && script.lang
   const scriptSetupLang = scriptSetup && scriptSetup.lang
 
-  let refBindings: string[] | undefined
-
   if (!scriptSetup) {
     if (!script) {
       throw new Error(`[@vue/compiler-sfc] SFC contains no <script> tags.`)
@@ -740,12 +738,6 @@ export function compileScript(
   for (const key in setupBindings) {
     ctx.bindingMetadata[key] = setupBindings[key]
   }
-  // known ref bindings
-  if (refBindings) {
-    for (const key of refBindings) {
-      ctx.bindingMetadata[key] = BindingTypes.SETUP_REF
-    }
-  }
 
   // 7. inject `useCssVars` calls
   if (