[modules] Give Module an internal [hash] field

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 163e86484dfb7f4d9f1ebd9c9ea02a8bf0ad51c2..664697921b915c7b148f4a9b1301354b13a30e42 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1758,17 +1758,13 @@ Handle<Module> Factory::NewModule(Handle<SharedFunctionInfo> code) {
       requested_modules_length > 0 ? NewFixedArray(requested_modules_length)
                                    : empty_fixed_array();
 
-  // To make it easy to hash Modules, we set a new symbol as the name of
-  // SharedFunctionInfo representing this Module.
-  Handle<Symbol> name_symbol = NewSymbol();
-  code->set_name(*name_symbol);
-
   Handle<Module> module = Handle<Module>::cast(NewStruct(MODULE_TYPE));
   module->set_code(*code);
   module->set_exports(*exports);
   module->set_requested_modules(*requested_modules);
   module->set_flags(0);
   module->set_embedder_data(isolate()->heap()->undefined_value());
+  module->set_hash(isolate()->GenerateIdentityHash(Smi::kMaxValue));
   return module;
 }