JIRA: https://jira.spring.io/browse/INT-3667
* fix `RedisLockRegistry.tryLock` memory leaks using 2 different thread local internal storages:
hard references for locked locks and weak references (optional) for others, weak references are used for lock obtaining optimization -
thread will get same `RedisLock` object for certain key before locking and after unlocking (if variable still exists)
* add `RedisLockRegistry.useWeakReferences` property for enable thread local weak references storage for unlocked locks, disabled by default
* fix `RedisLockRegistry$RedisLock.obtainLock` improper expire time update (expire time was updated on every attempt to get lock)
* update `RedisLockRegistry` tests
efef65c52f