Issue #1833442 by rootatwc, dawehner, alexpott: Remove hook_boot().

core/includes/bootstrap.inc

core/includes/common.inc

core/includes/menu.inc

core/includes/path.inc

...upal/language/Tests/LanguageUILanguageNegotiationTest.php

core/modules/language/tests/language_test/language_test.info

...modules/language/tests/language_test/language_test.module

...uage_test/lib/Drupal/language_test/LanguageTestBundle.php

...age_test/lib/Drupal/language_test/LanguageTestManager.php

...em/lib/Drupal/system/Tests/Bootstrap/HookBootExitTest.php

...es/system/lib/Drupal/system/Tests/Session/SessionTest.php

core/modules/system/system.api.php

core/modules/system/system.module

...al/session_test/EventSubscriber/SessionTestSubscriber.php

...ession_test/lib/Drupal/session_test/SessionTestBundle.php

...les/system/tests/modules/session_test/session_test.module

...dules/system/tests/modules/system_test/system_test.module

core/modules/translation/tests/translation_test.module