Fatal error: Uncaught Error: Class "Drupal\Core\Extension\ExtensionList" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Extension/ModuleExtensionList.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Extension/ModuleExtensionList.php on line 13