Add a unit test for decompInit_lnd

Add a PF unittest for decompInit_lnd as a way to make sure things work with changes to decompInit especially for mpi-serial mode. Initially this will just be with our serial unittesting, but we should evaluate if we could expand to running the PR unittest framework in parallel. This can also be a spring forward for being able to add self-testing to decompInit to make sure it's working correctly. I think both might be important to get a reasonable testing framework to do this work in.