Add a unit test for decompInit_lnd

[ekluzek]

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.

[ekluzek]

I got into this, and ran into many problems. So I think I need to retire this idea. It turns out that using decompInit requires some FATES code. And it also needs a real shr_mpi_mod rather than the stub version. The PF unit framework is currently setup without MPI, and looking into it, although pFUnit is intended to run parallel, we only build the NOMPI version. So it would be hard to extend it to MPI versions.

I tried adding FATES code and could probably get that to work, but it wasn't easy in and of itself.

[ekluzek]

I'm reopening this based on my work with self-tests for doing some of this. I realize that a unittest for decompInit for at least the error testing would be preferred from using the self-tests for it. We have concluded that adding PFUNIT to the model buld for self-tests nor making a parallel build for unit testing is a good direction to go right now.

But, adding FATES code to the unit tests AND building the unit tests with mpi-serial -- might be doable and allow this as well as other testing. So I'm going to explore that again and see if it's reasonable enough to do.