[SQL] Turns on in-memory columnar compression in HiveCompatibilitySuite

`HiveCompatibilitySuite` already turns on in-memory columnar caching, it would be good to also enable compression to improve test coverage.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #2190 from liancheng/compression-on and squashes the following commits:

88b536c [Cheng Lian] Code cleanup, narrowed field visibility
d13efd2 [Cheng Lian] Turns on in-memory columnar compression in HiveCompatibilitySuite