diff -u b/core/includes/common.inc b/core/includes/common.inc
--- b/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -3889,7 +3889,7 @@
     // this is an AJAX request.
     // @todo Clean up container call.
     $container = drupal_container();
-    if ($container->has('request') && $container->has('content_negotiation') && $container->isScopeActive('request')) {
+    if ($container->has('content_negotiation') && $container->isScopeActive('request')) {
       $type = $container->get('content_negotiation')->getContentType($container->get('request'));
     }
     if (!empty($items['settings']) || (!empty($type) && $type == 'ajax')) {
diff -u b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
--- b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -673,7 +673,6 @@
     // container in drupal_container(). Drupal\simpletest\TestBase::tearDown()
     // restores the original container.
     // @see Drupal\Core\DrupalKernel::initializeContainer()
-    drupal_container(NULL, TRUE);
     $this->kernel = new DrupalKernel('testing', FALSE, system_list());
     // Booting the kernel is necessary to initialize the new DIC. While
     // normally the kernel gets booted on demand in
reverted:
--- b/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Container.php
+++ a/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Container.php
@@ -252,9 +252,6 @@
             try {
                 $service = $this->$method();
             } catch (\Exception $e) {
-              if ($id == 'request') {
-                $x=0;
-              }
                 unset($this->loading[$id]);
                 throw $e;
             }