bug #2110 fix(symfony): serializer (GuigZ-)

This PR was submitted for the 2.x branch but it was squashed and merged into the 2.7 branch instead (closes #2110).

Discussion
----------

fix(symfony): serializer

Use case : https://github.com/GuigZ-/fosrest-symfony-44-serializer

Just start a server : `bin/console server:start`

Commits
-------

98aebda fix(symfony): serializer

Author: xabbuh

Serializer/Normalizer/ExceptionNormalizer.php

@@ -41,6 +41,6 @@ public function normalize($object, $format = null, array $context = [])
      */
     public function supportsNormalization($data, $format = null)
     {
-        return $data instanceof \Exception;
+        return $data instanceof \Throwable;
     }
 }