[modules] Implement @@iterator on namespace objects.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index b66a5ec1a273def680d8b34fea1e4180fdcfa27e..0800ec69dcea25a25388fd647a4ad7fcec87f340 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -702,6 +702,7 @@ TYPE_CHECKER(FixedDoubleArray, FIXED_DOUBLE_ARRAY_TYPE)
 TYPE_CHECKER(WeakFixedArray, FIXED_ARRAY_TYPE)
 TYPE_CHECKER(TransitionArray, TRANSITION_ARRAY_TYPE)
 TYPE_CHECKER(JSStringIterator, JS_STRING_ITERATOR_TYPE)
+TYPE_CHECKER(JSFixedArrayIterator, JS_FIXED_ARRAY_ITERATOR_TYPE)
 
 bool HeapObject::IsJSWeakCollection() const {
   return IsJSWeakMap() || IsJSWeakSet();
@@ -2114,6 +2115,8 @@ int JSObject::GetHeaderSize(InstanceType type) {
       return JSObject::kHeaderSize;
     case JS_STRING_ITERATOR_TYPE:
       return JSStringIterator::kSize;
+    case JS_FIXED_ARRAY_ITERATOR_TYPE:
+      return JSFixedArrayIterator::kHeaderSize;
     default:
       UNREACHABLE();
       return 0;
@@ -3283,6 +3286,7 @@ CAST_ACCESSOR(JSMap)
 CAST_ACCESSOR(JSMapIterator)
 CAST_ACCESSOR(JSMessageObject)
 CAST_ACCESSOR(JSModuleNamespace)
+CAST_ACCESSOR(JSFixedArrayIterator)
 CAST_ACCESSOR(JSObject)
 CAST_ACCESSOR(JSProxy)
 CAST_ACCESSOR(JSReceiver)
@@ -5725,6 +5729,10 @@ ACCESSORS(ContextExtension, extension, Object, kExtensionOffset)
 
 ACCESSORS(JSModuleNamespace, module, Module, kModuleOffset)
 
+ACCESSORS(JSFixedArrayIterator, array, FixedArray, kArrayOffset)
+SMI_ACCESSORS(JSFixedArrayIterator, index, kIndexOffset)
+ACCESSORS(JSFixedArrayIterator, initial_next, JSFunction, kNextOffset)
+
 ACCESSORS(Module, code, Object, kCodeOffset)
 ACCESSORS(Module, exports, ObjectHashTable, kExportsOffset)
 ACCESSORS(Module, module_namespace, HeapObject, kModuleNamespaceOffset)