Fixing merge with 8.x upstream.

core/CHANGELOG.txt

core/includes/bootstrap.inc

core/includes/common.inc

core/includes/registry.inc

core/includes/unicode.inc

core/includes/update.inc

core/modules/color/color.install

core/modules/comment/comment.pages.inc

core/modules/comment/comment.test

core/modules/contact/contact.admin.inc

core/modules/contact/contact.test

core/modules/field/field.module

core/modules/file/file.install

core/modules/image/image.install

core/modules/language/language.info

core/modules/language/language.negotiation.inc

...rupal/language/Tests/LanguageBrowserDetectionUnitTest.php

...e/lib/Drupal/language/Tests/LanguageConfigurationTest.php

...Drupal/language/Tests/LanguageDependencyInjectionTest.php

...s/language/lib/Drupal/language/Tests/LanguageListTest.php