Merge branch '3.3' into 3.4

* 3.3: (22 commits)
  [Routing] Fix resource miss
  [Security] Fixed auth provider authenticate() cannot return void
  declare argument type
  [FrameworkBundle][Serializer] Move normalizer/encoders definitions to xml file & remove unnecessary checks
  streamed response should return $this
  $isClientIpsVali is not used
  content can be a resource
  Adding the Form default theme files to be warmed up in Twig's cache
  Remove BC Break label from `NullDumper` class
  Username and password in basic auth are allowed to contain '.'
  Remove obsolete PHPDoc from UriSigner
  [Serializer] YamlEncoder: throw if the Yaml component isn't installed
  [Serializer] ObjectNormalizer: throw if PropertyAccess isn't installed
  [PropertyInfo] Add support for the iterable type
  pdo session fix
  Fixed pathinfo calculation for requests starting with a question mark.  - fix bad conflict resolving issue  - port symfony/symfony#21968 to 3.3+
  Fixed unsetting from loosely equal keys OrderedHashMap
  add DOMElement as return type in Crawler::getIterator to support foreach support in ide
  Fixed mistake in exception expectation
  [Debug] Fix same vendor detection in class loader
  ...

Author: fabpot

Crawler.php

@@ -1071,7 +1071,7 @@ public function count()
     }
 
     /**
-     * @return \ArrayIterator
+     * @return \ArrayIterator|\DOMElement[]
      */
     public function getIterator()
     {