Merge branch '4.3' into 4.4

* 4.3: (26 commits)
  Fix Twig 1.x compatibility
  [Translator] Improve farsi(persian) translations for Form
  Improve fa translations
  Spell "triggering" properly
  Added tests to cover the possibility of having scalars as services.
  fixed tests on old PHP versions
  [FrameworkBundle] Inform the user when save_path will be ignored
  fixed CS
  [SecurityBundle] Fix profiler dump for non-invokable security listeners
  fixed CS
  [Messenger] Doctrine Transport: Support setting auto_setup from DSN
  [Translator] Load plurals from po files properly
  [Serializer]: AbstractObjectNormalizer ignores the property types of discriminated classes
  [EventDispatcher] Add tag kernel.rest on 'debug.event_dispatcher' service
  [Console] Update to inherit and add licence
  Add missing test for workflow dump description
  [Intl] Remove --dev from intl compile autoloader
  [Messenger] fix publishing headers set on AmqpStamp
  Remove call to deprecated method
  [Intl] Init compile tmp volume
  ...

Controller/ExceptionController.php

@@ -64,7 +64,7 @@ public function showAction($token)
         $exception = $this->profiler->loadProfile($token)->getCollector('exception')->getException();
         $template = $this->getTemplate();
 
-        if (!$this->twig->getLoader()->exists($template)) {
+        if (!$this->templateExists($template)) {
             return new Response($this->errorRenderer->getBody($exception), 200, ['Content-Type' => 'text/html']);
         }