Fixes issue #3508803: Fixed PHPCS issues

Closes #3508803

tests/modules/site_settings_sample_data/site_settings_sample_data.install

@@ -149,7 +149,6 @@ function site_settings_sample_data_install() {
   $site_setting->save();
 
   // Create txt file.
-  global $base_url;
   $data = file_get_contents($base_url . '/README.md');
   /** @var \Drupal\file\FileRepositoryInterface $file_repository */
   $file_repository = \Drupal::service('file.repository');