fix(runtime-core/template-refs): do not reset refs object before updates

fix #2283

packages/runtime-core/src/renderer.ts

@@ -1456,11 +1456,6 @@ function baseCreateRenderer(
         const prevTree = instance.subTree
         instance.subTree = nextTree
 
-        // reset refs
-        // only needed if previous patch had refs
-        if (instance.refs !== EMPTY_OBJ) {
-          instance.refs = {}
-        }
         if (__DEV__) {
           startMeasure(instance, `patch`)
         }