[modules] Implement @@iterator on namespace objects.

src/builtins/builtins.h

Index: src/builtins/builtins.h
diff --git a/src/builtins/builtins.h b/src/builtins/builtins.h
index d370e936907623c6587aad3351bfcf4146884b28..6624e6ea60a95865ebd297db712b4b7ce6c7dba5 100644
--- a/src/builtins/builtins.h
+++ b/src/builtins/builtins.h
@@ -665,7 +665,10 @@ namespace internal {
   /* ES6 section 22.2.3.3 get %TypedArray%.prototype.byteOffset */            \
   TFJ(TypedArrayPrototypeByteOffset, 1)                                       \
   /* ES6 section 22.2.3.18 get %TypedArray%.prototype.length */               \
-  TFJ(TypedArrayPrototypeLength, 1)
+  TFJ(TypedArrayPrototypeLength, 1)                                           \
+                                                                              \
+  CPP(ModuleNamespaceIterator)                                                \
+  CPP(FixedArrayIteratorNext)
 
 #define IGNORE_BUILTIN(...)