[modules] Implement @@iterator on namespace objects.

src/ast/ast-types.cc

Index: src/ast/ast-types.cc
diff --git a/src/ast/ast-types.cc b/src/ast/ast-types.cc
index 3f85f479e9e78cfeafd23522f085c6c6e1a8106f..25691e455b14b6eda7722c586f68d6176a52fba7 100644
--- a/src/ast/ast-types.cc
+++ b/src/ast/ast-types.cc
@@ -209,6 +209,7 @@ AstType::bitset AstBitsetType::Lub(i::Map* map) {
     case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
     case JS_GENERATOR_OBJECT_TYPE:
     case JS_MODULE_NAMESPACE_TYPE:
+    case JS_FIXED_ARRAY_ITERATOR_TYPE:
     case JS_ARRAY_BUFFER_TYPE:
     case JS_ARRAY_TYPE:
     case JS_REGEXP_TYPE:  // TODO(rossberg): there should be a RegExp type.