Remove support for object grouping during Garbage Collection

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 100c316f8b7fb1ecccaf76a715d14dcd6ca35d58..15a5973585273b125e58e22be4f93d46235bc2c6 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -19379,11 +19379,9 @@ static FinalizablePersistentHandle* AddFinalizer(
     Dart_WeakPersistentHandleFinalizer callback) {
   ASSERT((callback != NULL && peer != NULL) ||
          (callback == NULL && peer == NULL));
-  const bool is_prologue = false;
   // TODO(19482): Make API consistent for external size of strings/typed data.
   const intptr_t external_size = 0;
   return FinalizablePersistentHandle::New(Isolate::Current(),
-                                          is_prologue,
                                           referent,
                                           peer,
                                           callback,