[Form, FrameworkBundle] added csrf tokens reset on Kernel::shutdown() to preven tokens stacking in tests

src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php

@@ -37,6 +37,9 @@ class FrameworkBundle extends Bundle
         if ($this->container->has('error_handler')) {
             $this->container->get('error_handler');
         }
+
+        FormConfiguration::clearDefaultCsrfSecrets();
+
         if ($this->container->hasParameter('csrf_secret')) {
             FormConfiguration::addDefaultCsrfSecret($this->container->getParameter('csrf_secret'));
             FormConfiguration::enableDefaultCsrfProtection();

src/Symfony/Component/Form/FormConfiguration.php

@@ -108,6 +108,11 @@ class FormConfiguration
         self::$defaultCsrfSecrets[] = $secret;
     }
 
+    static public function clearDefaultCsrfSecrets()
+    {
+        self::$defaultCsrfSecrets = array();
+    }
+
     /**
      * Returns the default CSRF secrets
      *