Merge branch '6.0' into 6.1

* 6.0: (23 commits)
  Fix composer on appveyor
  fix bootstrap_3_layout ChoiceType's expanded label_html
  [Messenger][Security/Core] Remove legacy class aliases
  [PropertyAccess] Fix typo in PropertyAccessor::readProperty() DocBlock
  [PropertyInfo] PhpStanExtractor namespace missmatch issue
  [VarExporter] Fix exporting objects with readonly properties
  [ExpressionLanguage] Fix matches when the regexp is not valid
  [Messenger] Add mysql indexes back and work around deadlocks using soft-delete
  Add BC layer to handle old objects already present in cache
  [RateLimiter] Always store SlidingWindows with an expiration set
  [Validator] Fix File constraint invalid max size exception message
  [Console] Fix exit status on uncaught exception with negative code
  [Validator] fix #43345 @Assert\DivisibleBy
  [HttpClient] fix 303 after PUT and sending chunked requests
  [HttpClient] always send Content-Type when a body is passed
  [HttpClient] always send Content-Length when a body is passed
  [HttpClient] fix sending Content-Length/Type for POST
  Fix merge
  [HttpClient] fix sending PUT requests with curl
  Fix locales format in CrowdinProvider
  ...

Author: nicolas-grekas

Authorization/TraceableAccessDecisionManager.php

@@ -108,7 +108,3 @@ public function getDecisionLog(): array
         return $this->decisionLog;
     }
 }
-
-if (!class_exists(DebugAccessDecisionManager::class, false)) {
-    class_alias(TraceableAccessDecisionManager::class, DebugAccessDecisionManager::class);
-}

Exception/UserNotFoundException.php

@@ -71,7 +71,3 @@ public function __unserialize(array $data): void
         parent::__unserialize($parentData);
     }
 }
-
-if (!class_exists(UsernameNotFoundException::class, false)) {
-    class_alias(UserNotFoundException::class, UsernameNotFoundException::class);
-}

Tests/Authorization/TraceableAccessDecisionManagerTest.php

@@ -15,7 +15,6 @@
 use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
 use Symfony\Component\Security\Core\Authorization\AccessDecisionManager;
 use Symfony\Component\Security\Core\Authorization\AccessDecisionManagerInterface;
-use Symfony\Component\Security\Core\Authorization\DebugAccessDecisionManager;
 use Symfony\Component\Security\Core\Authorization\TraceableAccessDecisionManager;
 use Symfony\Component\Security\Core\Authorization\Voter\VoterInterface;
 
@@ -171,13 +170,6 @@ public function provideObjectsAndLogs(): \Generator
         ];
     }
 
-    public function testDebugAccessDecisionManagerAliasExistsForBC()
-    {
-        $adm = new TraceableAccessDecisionManager(new AccessDecisionManager());
-
-        $this->assertInstanceOf(DebugAccessDecisionManager::class, $adm, 'For BC, TraceableAccessDecisionManager must be an instance of DebugAccessDecisionManager');
-    }
-
     /**
      * Tests decision log returned when a voter call decide method of AccessDecisionManager.
      */