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
@@ -773,6 +773,10 @@
     if (!$this->setupDatabasePrefix) {
       return FALSE;
     }
+    // Destroy the testing kernel.
+    if (isset($this->kernel)) {
+      $this->kernel->shutdown();
+    }
     // Remove all prefixed tables.
     $connection_info = Database::getConnectionInfo('default');
     $tables = db_find_tables($connection_info['default']['prefix']['default'] . '%');
@@ -807,11 +811,6 @@
     // Rebuild caches.
     $this->refreshVariables();
 
-    // Destroy the testing kernel.
-    if (isset($this->kernel)) {
-      $this->kernel->shutdown();
-    }
-
     // Close the CURL handler.
     $this->curlClose();
   }