Reland: [modules] Properly initialize declared variables.

src/ast/scopes.cc

Index: src/ast/scopes.cc
diff --git a/src/ast/scopes.cc b/src/ast/scopes.cc
index 9e77b5145265eee9906f0c4a155cae246c6cf369..b6d4b2176ec5cfb339f7f949706903f8e6cb61c5 100644
--- a/src/ast/scopes.cc
+++ b/src/ast/scopes.cc
@@ -152,7 +152,8 @@ DeclarationScope::DeclarationScope(Zone* zone, Scope* outer_scope,
 
 ModuleScope::ModuleScope(DeclarationScope* script_scope,
                          AstValueFactory* ast_value_factory)
-    : DeclarationScope(ast_value_factory->zone(), script_scope, MODULE_SCOPE) {
+    : DeclarationScope(ast_value_factory->zone(), script_scope, MODULE_SCOPE,
+                       kModule) {
   Zone* zone = ast_value_factory->zone();
   module_descriptor_ = new (zone) ModuleDescriptor(zone);
   set_language_mode(STRICT);