message: Fix an incorrect assertion
  `m_notifier_skip_version` is set to 0 before this point and `skip_version` is
  the actual value which should be checked.
  TSan complained about a data race on the member variable as we've dropped the
  lock at the point of the assert.
diff: @@ -1005,7 +1005,7 @@ void RealmCoordinator::run_async_notifiers()
  version = m_db->get_version_id_of_latest_snapshot();
  if (version == m_notifier_sg->get_version_of_current_transaction()) {
  // We were spuriously woken up and there isn't actually anything to do
  - REALM_ASSERT(!m_notifier_skip_version.version);
  + REALM_ASSERT(!skip_version.version);
  m_notifier_cv.notify_all();
  return;
  }
  