Merge branch '4.3' into 4.4

* 4.3:
  fixed CS
  fixed CS
  fixed CS
  Do not log or call the proxy function when the locale is the same
  Added missing required dependencies on psr/cache and psr/container in symfony/cache-contracts and symfony/service-contracts respectively.
  [HttpClient] fix closing debug stream prematurely
  [Mailer] made code more robust
  Restore compatibility with php 5.5
  fixed sender/recipients in SMTP Envelope
  collect called listeners information only once
  [HttpKernel] Remove TestEventDispatcher.

Author: fabpot

Filesystem.php

@@ -744,15 +744,15 @@ private function getSchemeAndHierarchy(string $filename): array
     private static function box($func)
     {
         self::$lastError = null;
-        \set_error_handler(__CLASS__.'::handleError');
+        set_error_handler(__CLASS__.'::handleError');
         try {
             $result = $func(...\array_slice(\func_get_args(), 1));
-            \restore_error_handler();
+            restore_error_handler();
 
             return $result;
         } catch (\Throwable $e) {
         }
-        \restore_error_handler();
+        restore_error_handler();
 
         throw $e;
     }