[turbofan] Non-dictionary prototype maps are always stable.

src/compiler/js-native-context-specialization.h

Index: src/compiler/js-native-context-specialization.h
diff --git a/src/compiler/js-native-context-specialization.h b/src/compiler/js-native-context-specialization.h
index 6556e9e7445a899d213490f9fffed03928176554..26fe9273926cb446f8a2fac868232620a5221697 100644
--- a/src/compiler/js-native-context-specialization.h
+++ b/src/compiler/js-native-context-specialization.h
@@ -72,6 +72,10 @@ class JSNativeContextSpecialization final : public AdvancedReducer {
   bool LookupInScriptContextTable(Handle<Name> name,
                                   ScriptContextTableLookupResult* result);
 
+  // Adds stability dependencies on all prototypes of every class in
+  // {receiver_type} up to (and including) the {holder}.
+  void AssumePrototypesStable(Type* receiver_type, Handle<JSObject> holder);
+
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }
   Isolate* isolate() const;