[Validator] fix return doc of ClassMetadata::getCascadingStrategy
[Validator] remove duplicate interface implementations
Merge branch '2.5'

* 2.5:
  [DependencyInjection] fix @return anno created by PhpDumper
  Fixed the phpdoc of the VoterInterface
  [DoctrineBridge] Fix empty parameter logging in the dbal logger
  [Validator] remove duplicate interface implementations
  [Validator] fix return doc of ClassMetadata::getCascadingStrategy
  Fixed #11675 ValueToDuplicatesTransformer accept "0" value
  check for the correct field type
  fix handling of nullable XML attributes
  [DomCrawler] fix the axes handling in a bc way