Simplify check and remove outdated comment.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 418df559da2480230dd6e3b6e5d813a6b146f6d9..3f92c595c7fd899bdc7d80b5c599d420691ac849 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -5326,8 +5326,7 @@ bool Code::IsWeakObjectInOptimizedCode(Object* object) {
   } else if (object->IsPropertyCell()) {
     object = PropertyCell::cast(object)->value();
   }
-  if (object->IsJSObject() || object->IsJSProxy()) {
-    // JSProxy is handled like JSObject because it can morph into one.
+  if (object->IsJSReceiver()) {
     return FLAG_weak_embedded_objects_in_optimized_code;
   }
   if (object->IsFixedArray()) {