Merge remote-tracking branch 'upstream/8.x' into kernel

core/includes/bootstrap.inc

core/includes/config.inc

core/includes/form.inc

core/includes/install.core.inc

core/includes/install.inc

...rupal/Core/Config/ConfigFileStorageSignatureException.php

core/lib/Drupal/Core/Config/DrupalConfigVerifiedStorage.php

...upal/Core/Config/DrupalConfigVerifiedStorageInterface.php

core/lib/Drupal/Core/Config/FileStorage.php

core/misc/ajax.js

core/misc/authorize.js

core/misc/autocomplete.js

core/misc/batch.js

core/misc/collapse.js

core/misc/drupal.js

core/misc/form.js

core/misc/machine-name.js

core/misc/progress.js

core/misc/states.js

core/misc/tabledrag.js