Speed up Sentinel related tests

* remove FIXME sleep codes for Sentinel related tests
** add functions for Sentinel tests (JedisSentinelTestUtil)
*** waitForSentinelRecognizeRedisReplication
*** waitForNewPromotedMaster
*** waitForSentinelsRecognizeEachOthers
**** TODO: there're no command for sentinel to list recognized sentinel
**** sleep 5.5 sec (sentinel pings to master every 5 sec)

* set HostAndPort class to public(no longer inner) class
** reason: We cannot know pool's current master if HostAndPort class is
private inner class / HostAndPort classes are duplicated (main/test)
** make getter method and parameterized constructor
*** set fields once, get anytime