[es6] silence access-check failure for well-known symbol properties

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 01e1de22b0ca11993a7472d4159a5ae2a9b9094e..f914156e985ae83f07fbcee03c24b4c4ccbb59df 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6793,6 +6793,12 @@ Local<Symbol> v8::Symbol::GetToStringTag(Isolate* isolate) {
 }
 
 
+Local<Symbol> v8::Symbol::GetIsConcatSpreadable(Isolate* isolate) {
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  return Utils::ToLocal(i_isolate->factory()->is_concat_spreadable_symbol());
+}
+
+
 Local<Number> v8::Number::New(Isolate* isolate, double value) {
   i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
   if (std::isnan(value)) {