Merge branch '3.4' into 4.4

* 3.4:
  Fixes sprintf(): Too few arguments in form transformer
  [Console] Fix QuestionHelper::disableStty()
  validate subforms in all validation groups
  Update Hungarian translations
  Add meaningful message when Process is not installed (ProcessHelper)
  [PropertyAccess] Fix TypeError parsing again.
  [Form] add missing Czech validators translation
  [Validator] add missing Czech translations
  never directly validate Existence (Required/Optional) constraints

Author: nicolas-grekas

Command/ServerLogCommand.php

@@ -106,7 +106,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         }
 
         if (!$socket = stream_socket_server($host, $errno, $errstr)) {
-            throw new RuntimeException(sprintf('Server start failed on "%s": '.$errstr.' '.$errno, $host));
+            throw new RuntimeException(sprintf('Server start failed on "%s": ', $host).$errstr.' '.$errno);
         }
 
         foreach ($this->getLogs($socket) as $clientId => $message) {