feat(reactivity): collection iteration should inherit iterator instance methods

packages/reactivity/src/collectionHandlers.ts

@@ -55,7 +55,10 @@ function createIterableMethod(
       )
     // return a wrapped iterator which returns observed versions of the
     // values emitted from the real iterator
-    return {
+    return extend(
+      // inheriting all iterator properties
+      Object.create(innerIterator),
+      {
         // iterator protocol
         next() {
           const { value, done } = innerIterator.next()
@@ -70,7 +73,8 @@ function createIterableMethod(
         [Symbol.iterator]() {
           return this
         },
-    }
+      },
+    )
   }
 }