Sentinel unit test revised (use "sentinel failover", take care of "-failover-abort", etc)

Summary 
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* Use "sentinel failover" to force failover
  * From now on, no need to kill Redis Server instance
  * Reduced 1 Redis Server and 1 Sentinel instances, and shift instances' port / index to remove unused index
* Let JedisSentinelPoolTest recognizes "aborted failover" and fail fast
  * unit test fails immediately when -failover-aborted-* event occurred
* set sentinel failover-timeout shorter
* Refactor JedisSentinelTest, JedisSentinelPoolTest, JedisSentinelTestUtil 

See https://travis-ci.org/HeartSaVioR/jedis/builds/18929231 for review build status.

ps. d937b48f9093b9e0bfa85eadc595c4e542c95d17 is reverted commit of  57b17dcc7114e3b6788a9332a0a1127cbcf793ba, so it would be good to cherry-pick things.
(removing two commits and applying a3862bc2dd96805b85d2a99ed03e5d76c615e1d9 make senses)

I'm not good at git rebase, so I need your help. :)
I'll make PR again with cleanup if you want.