fix(runtime-core/emits): merge emits options from mixins/extends

fix #1562

packages/runtime-core/src/componentProps.ts

@@ -242,8 +242,6 @@ function setFullProps(
   attrs: Data
 ) {
   const [options, needCastKeys] = normalizePropsOptions(instance.type)
-  const emits = instance.type.emits
-
   if (rawProps) {
     for (const key in rawProps) {
       const value = rawProps[key]
@@ -256,7 +254,7 @@ function setFullProps(
       let camelKey
       if (options && hasOwn(options, (camelKey = camelize(key)))) {
         props[camelKey] = value
-      } else if (!emits || !isEmitListener(emits, key)) {
+      } else if (!isEmitListener(instance.type, key)) {
         // Any non-declared (either as a prop or an emitted event) props are put
         // into a separate `attrs` object for spreading. Make sure to preserve
         // original key casing