[strong] Fix super in strong classes

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index a90f9c9e46849c56ae8efcd1102c20c1e333d61a..c8d2cad2aeaf6982100b8780fbf40504b4e393ee 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -779,11 +779,18 @@ void Isolate::ReportFailedAccessCheck(Handle<JSObject> receiver) {
 
 
 bool Isolate::IsInternallyUsedPropertyName(Handle<Object> name) {
+  if (name->IsSymbol()) {
+    return Handle<Symbol>::cast(name)->is_private() &&
+           Handle<Symbol>::cast(name)->is_own();
+  }
   return name.is_identical_to(factory()->hidden_string());
 }
 
 
 bool Isolate::IsInternallyUsedPropertyName(Object* name) {
+  if (name->IsSymbol()) {
+    return Symbol::cast(name)->is_private() && Symbol::cast(name)->is_own();
+  }
   return name == heap()->hidden_string();
 }