Updated to Drupal 8.5. Core Media not yet in use.

[yaffs-website] / web / core / modules / system / tests / modules / theme_test / theme_test.libraries.yml

theme_stylesheets_override_and_remove_test:
  version: VERSION
  css:
    base:
      css/base-remove.css: {}
      css/sub-override.css: {}
      css/sub-remove.css: {}