Add Compression::Test which pretends paccking but does not nothing usefull. It's only called from test for now. Depends on D114493.

Add Compression::Test type which just pretends packing, but does nothing useful. It's only called from test for now. Depends on D114493.

Add Compression::Test type which just pretends paccking but does not, but does nothing usefulll. It's only called from test for now. Depends on D114493.