Jedis Test improvements

[Gabriel Erzse]

Improve the testing area in Jedis, across two directions:

• get more code coverage;

• run against different flavors of Redis, and don't build Redis from source.

• #3710

• #3711

• #3712

• #3713

• #3714

• #3471

• #3709

• #3708

• #2367

• #3410

• #3715

• #3716

• #3717

• #3718

• #3719

• #3720

• #3125

• #3721