Issue #2263201 by alexpott: ConfigImportUITest has a random failure.
Issue #2012468 by blueminds, plach: Add trusted roles recommendation to 'access site reports'.
Issue #2262483 by sun: Some PHPUnit tests do not exist.
Issue #2256405 by blueminds: VocabularyUnitTest and VocabularyTest are misnamed.
Merge branch '8.x' into 2262863-image-srcset
Merge branch '2260061-picture-polyfill-2' of github.com:attiks/drupal into 2260061-picture-polyfill-2