bug #32464 [WebProfilerBundle] Fix Twig 1.x compatibility (yceruto)

This PR was merged into the 3.4 branch.

Discussion
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[WebProfilerBundle] Fix Twig 1.x compatibility

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | not needed

Commits
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a9a6eb5 Fix Twig 1.x compatibility

src/Symfony/Bundle/WebProfilerBundle/Controller/ExceptionController.php

@@ -60,7 +60,7 @@ 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)) {
             $handler = new ExceptionHandler($this->debug, $this->twig->getCharset(), $this->fileLinkFormat);
 
             return new Response($handler->getContent($exception), 200, ['Content-Type' => 'text/html']);