Merge branch '5.3' into 5.4

* 5.3:
  [Security] Do not overwrite already stored tokens for REMOTE_USER authentication
  [Validator] Fix validation for single level domains
  Fix redundant type casts
  Increased the reserved memory from 10k to 32k
  [DoctrineBridge] Add DbalLoggerTest to group legacy
  Leverage DBAL's getNativeConnection() method
  Fix idempotency of LocoProvider write method

Author: nicolas-grekas

Question/Question.php

@@ -127,7 +127,7 @@ public function isHiddenFallback()
      */
     public function setHiddenFallback(bool $fallback)
     {
-        $this->hiddenFallback = (bool) $fallback;
+        $this->hiddenFallback = $fallback;
 
         return $this;
     }