CBQE-0: create wrapper for run_compaction and get_db_info for CompactionTests.cc

Change-Id: I1abecd856b0d4f0f0ef6db710f2d646f5d5b427d
Reviewed-on: http://review.couchbase.org/44098
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>