minor #1842 don't set logout_on_user_change on Symfony 4.1 (xabbuh)

This PR was merged into the 2.3-dev branch.

Discussion
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don't set logout_on_user_change on Symfony 4.1

Commits
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0538e3b don't set logout_on_user_change on Symfony 4.1

Author: xabbuh

Tests/Functional/app/Configuration/security.php

@@ -1,12 +1,13 @@
 <?php
 
 use Symfony\Component\Security\Core\Security;
+use Symfony\Component\Security\Http\Controller\UserValueResolver;
 
 $defaultFirewall = [
     'anonymous' => null,
 ];
 
-if (method_exists(Security::class, 'getUser')) {
+if (method_exists(Security::class, 'getUser') && !class_exists(UserValueResolver::class)) {
     $defaultFirewall['logout_on_user_change'] = true;
 }