Add reference checking test that runs reconstruction and selection

This MR introduces a reference checking test that runs reconstruction and (ThOr) hlt2 selections. A set of generic lines (also included by this MR) is used in the test.

The Size of compressed data counter from HltPackedDataWriter has been included in the knows_fluctuating_counters list since it changes between runs (see LHCb#151 (closed)).

FYI: @sstahl @rmatev