Merge branch 'kernel-fabpot-review' into kernel

core/includes/common.inc

core/lib/Drupal/Core/ContentNegotiation.php

core/lib/Drupal/Core/DrupalKernel.php

core/lib/Drupal/Core/EventSubscriber/AccessSubscriber.php

core/lib/Drupal/Core/EventSubscriber/HtmlSubscriber.php

...rupal/Core/EventSubscriber/LegacyControllerSubscriber.php

core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php

core/lib/Drupal/Core/ExceptionController.php

core/lib/Drupal/Core/UrlMatcher.php

...r/Symfony/Component/ClassLoader/ClassCollectionLoader.php

...endor/Symfony/Component/ClassLoader/ClassMapGenerator.php

...mfony/Component/ClassLoader/DebugUniversalClassLoader.php

core/vendor/Symfony/Component/ClassLoader/LICENSE

core/vendor/Symfony/Component/ClassLoader/README.md

...or/Symfony/Component/ClassLoader/UniversalClassLoader.php

core/vendor/Symfony/Component/ClassLoader/composer.json

...dor/Symfony/Component/EventDispatcher/EventDispatcher.php

...ny/Component/EventDispatcher/EventDispatcherInterface.php

core/vendor/Symfony/Component/EventDispatcher/LICENSE

core/vendor/Symfony/Component/EventDispatcher/composer.json