Merge branch '2.8' into 3.4

* 2.8:
  [Intl] Update ICU data to 61.1
  [Validator] Add Japanese translation
  Support phpdbg SAPI in Debug::enable()
  [Ldap] cast to string when checking empty passwords
  [Validator] sync validator translation id
  no type errors with invalid submitted data types
  [FrameworkBundle] Partially revert HttpCache is not longer abstract (4d075da)
  [Finder] Fixed leading/trailing / in filename
  allow html5 compatible rendering of forms with null names
  Change datetime input to datetime-local

Author: fabpot

HttpCache/HttpCache.php

@@ -23,7 +23,7 @@
  *
  * @author Fabien Potencier <[email protected]>
  */
-class HttpCache extends BaseHttpCache
+abstract class HttpCache extends BaseHttpCache
 {
     protected $cacheDir;
     protected $kernel;