diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index c35e026..583b83c 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -388,7 +388,7 @@ public function getAppRoot() {
   /**
    * {@inheritdoc}
    */
-  public function boot($rebuild = FALSE) {
+  public function boot() {
     if ($this->booted) {
       return $this;
     }
@@ -423,7 +423,7 @@ public function boot($rebuild = FALSE) {
     $this->bootstrapContainer = new $class(Settings::get('bootstrap_container_definition', $this->defaultBootstrapContainerDefinition));
 
     // Initialize the container.
-    $this->initializeContainer($rebuild);
+    $this->initializeContainer();
 
     // Ensure mt_rand() is reseeded to prevent random values from one page load
     // being exploited to predict random values in subsequent page loads.
diff --git a/core/lib/Drupal/Core/DrupalKernelInterface.php b/core/lib/Drupal/Core/DrupalKernelInterface.php
index 739b48c..892952a 100644
--- a/core/lib/Drupal/Core/DrupalKernelInterface.php
+++ b/core/lib/Drupal/Core/DrupalKernelInterface.php
@@ -21,12 +21,9 @@
   /**
    * Boots the current kernel.
    *
-   * @param bool $rebuild
-   *   (optional) Whether to rebuild the container or not.
-   *
    * @return $this
    */
-  public function boot($rebuild = FALSE);
+  public function boot();
 
   /**
    * Shuts down the kernel.
diff --git a/core/lib/Drupal/Core/Test/TestRunnerKernel.php b/core/lib/Drupal/Core/Test/TestRunnerKernel.php
index 8c35baa..f19afb3 100644
--- a/core/lib/Drupal/Core/Test/TestRunnerKernel.php
+++ b/core/lib/Drupal/Core/Test/TestRunnerKernel.php
@@ -50,7 +50,7 @@ public function __construct($environment, $class_loader) {
   /**
    * {@inheritdoc}
    */
-  public function boot($rebuild = FALSE) {
+  public function boot() {
     // Ensure that required Settings exist.
     if (!Settings::getAll()) {
       new Settings(array(
@@ -70,7 +70,7 @@ public function boot($rebuild = FALSE) {
     // In addition, ensure that PHP errors are not hidden away in logs.
     ini_set('display_errors', TRUE);
 
-    parent::boot($rebuild);
+    parent::boot();
 
     $this->getContainer()->get('module_handler')->loadAll();
 
diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index d890b41..e19aeae 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -88,6 +88,13 @@
   protected $streamWrappers = array();
 
   /**
+   * The dependency injection container builder used in the test.
+   *
+   * @var \Symfony\Component\DependencyInjection\ContainerBuilder
+   */
+  protected $containerBuilder;
+
+  /**
    * {@inheritdoc}
    */
   function __construct($test_id = NULL) {
@@ -287,12 +294,11 @@ protected function tearDown() {
    * @see \Drupal\simpletest\KernelTestBase::disableModules()
    */
   public function containerBuild(ContainerBuilder $container) {
-    // Keep the container object around for tests.
-    $this->container = $container;
+    // Keep the container builder object around for tests.
     $this->containerBuilder = $container;
 
     // Set the default language on the minimal container.
-    $this->container->setParameter('language.default_values', $this->defaultLanguageData());
+    $container->setParameter('language.default_values', $this->defaultLanguageData());
 
     $container->register('lock', 'Drupal\Core\Lock\NullLockBackend');
     $container->register('cache_factory', 'Drupal\Core\Cache\MemoryBackendFactory');
@@ -509,10 +515,6 @@ protected function enableModules(array $modules) {
     $module_filenames = $module_handler->getModuleList();
     $this->kernel->updateModules($module_filenames, $module_filenames);
 
-    // Get a fresh container, because ::containerBuild set $this->container to
-    // the active container builder, but that is no longer the active container.
-    $this->container = $this->kernel->getContainer();
-
     // Ensure isLoaded() is TRUE in order to make _theme() work.
     // Note that the kernel has rebuilt the container; this $module_handler is
     // no longer the $module_handler instance from above.
diff --git a/core/modules/simpletest/src/TestBase.php b/core/modules/simpletest/src/TestBase.php
index 3efca1b..4104b4b 100644
--- a/core/modules/simpletest/src/TestBase.php
+++ b/core/modules/simpletest/src/TestBase.php
@@ -277,13 +277,6 @@
   protected $container;
 
   /**
-   * The dependency injection container builder used in the test.
-   *
-   * @var \Symfony\Component\DependencyInjection\ContainerBuilder
-   */
-  protected $containerBuilder;
-
-  /**
    * The config importer that can used in a test.
    *
    * @var \Drupal\Core\Config\ConfigImporter
diff --git a/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php b/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php
index d4f5c23..41afb2d 100644
--- a/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php
+++ b/core/modules/system/src/Tests/ServiceProvider/ServiceProviderTest.php
@@ -30,11 +30,6 @@ function testServiceProviderRegistration() {
     $definition = $this->containerBuilder->getDefinition('file.usage');
     $this->assertTrue($definition->getClass() == 'Drupal\\service_provider_test\\TestFileUsage', 'Class has been changed');
     $this->assertTrue(\Drupal::hasService('service_provider_test_class'), 'The service_provider_test_class service has been registered to the DIC');
-    // The event subscriber method in the test class calls drupal_set_message with
-    // a message saying it has fired. This will fire on every page request so it
-    // should show up on the front page.
-    //$this->drupalGet('');
-    //$this->assertText(t('The service_provider_test event subscriber fired!'), 'The service_provider_test event subscriber fired');
   }
 
   /**