[Validator] Replaced inexistent interface.

ClassMetadataFactoryInterface was removed in 2.3 and replaced with MetadataFactoryInterface.
Merge branch '2.3' into 2.4

* 2.3:
  [Debug] fixed unit tests
  Avoid notice from being *eaten* by fatal error.
  Teardown used wrong property
  Modified guessDefaultEscapingStrategy to not escape txt templates
  Fix DateType for 32bits computers.
  Fixed the registration of validation.xml file when the form is disabled
  Fixes #9633, Removed dependency to Symfony\Bundle\FrameworkBundle\Tests\TestCase
  [Validator] Replaced inexistent interface.
  When getting the session's id, check if the session is not closed
  Adjusting CacheClear Warmup method to namespaced kernels

Conflicts:
	src/Symfony/Bundle/FrameworkBundle/Command/CacheClearCommand.php