[Security/Http] Fix test relying on a private property

src/Symfony/Component/Security/Http/Tests/Firewall/AnonymousAuthenticationListenerTest.php

@@ -54,10 +54,9 @@ class AnonymousAuthenticationListenerTest extends \PHPUnit_Framework_TestCase
         $authenticationManager
             ->expects($this->once())
             ->method('authenticate')
-            ->with(self::logicalAnd(
+            ->with($this->callback(function ($token) {
-                       $this->isInstanceOf('Symfony\Component\Security\Core\Authentication\Token\AnonymousToken'),
+                return 'TheKey' === $token->getKey();
-                       $this->attributeEqualTo('key', 'TheKey')
+            }))
-            ))
             ->will($this->returnValue($anonymousToken))
         ;