Added unit test suite for locking and fixed admin tests
#1837214 - patch by chia - Fixed Predis locking implementation, PhpRedis to come later
#1837214 - patch by chia - Fixed PhpRedis lock implementation
Minor PhpRedis lock backend fixes
Fixes PHP WSOD due to circular autoload calls when invoking cache_get() in _registry_check_code().
Fixing a really odd bug with Predis and HGETALL, still not sure we or Predis is the real source, needs investigation.
#1871006 - authored by das-peter - Flaw in the implementation of DrupalCacheInterface ::clear() - missing cid array handling
#1887544 - by mrfelton - Avoid some PHP notices when not using nor Predis nor settings.php driven configuration
#1804908 - by mongolito404 - Fixed Predis password handling