[bootstrapper] add checks for variable bindings in native scripts.

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index 42f54edebbbb767012fbe02fda50741b804579aa..7b4d2746d7de9a27b9e961ac71d1a57b8282f1e7 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -1086,7 +1086,7 @@ void Shell::InstallUtilityScript(Isolate* isolate) {
           i::JSFunction::cast(*compiled_script)->shared()->script()))
       : i::Handle<i::Script>(i::Script::cast(
           i::SharedFunctionInfo::cast(*compiled_script)->script()));
-  script_object->set_type(i::Script::TYPE_NATIVE);
+  script_object->set_type(i::Script::TYPE_EXTENSION);
 }
 #endif  // !V8_SHARED