Remove update overrides and flush all caches.
This will need to be run once all (if any) updates are run. Do not call this while updates are running.
function update_flush_all_caches() {
unset($GLOBALS['conf']['container_bundles']['UpdateBundle']);
Drupal::service('kernel')
->updateModules(Drupal::moduleHandler()
->getModuleList());
// No updates to run, so caches won't get flushed later. Clear them now.
drupal_flush_all_caches();
}