Stateless dycore granule

[samkellerhals]

Removed prognostic state list, and thus any state. Swapping of now and new variables is done externally in Fortran. This lead to all timesteps verifying against the Fortran reference except one field mass_flx_ic, a major improvement over dycore verifying only in odd timesteps where no swapping was occurring. This suggests that the previous swapping/state in the granule introduces a bug somewhere.

Also added grid_init_dycore, which enables running dycore granule in parallel. There are still some issues with GHEX however. On GPU GHEX grid decomposition works, but then there are compilation errors in the stencils. On CPU the current GHEX build fails to allocate memory on the GPU, which might be due to it having been built in GPU mode.

[github-actions]

Mandatory Tests

Please make sure you run these tests via comment before you merge!

• cscs-ci run default
• launch jenkins spack

Optional Tests

To run benchmarks you can use:

• cscs-ci run benchmark

To run tests and benchmarks with the DaCe backend you can use:

• cscs-ci run dace

In case your change might affect downstream icon-exclaim, please consider running

• launch jenkins icon

For more detailed information please look at CI in the EXCLAIM universe.