Add missing p4est functions with nonconservative terms

[benegee]

When using nonconservative terms in equations,

• 2D calc_mpi_interface_flux
• 2D calc_mpi_mortar_flux
• 3D calc_boundary_flux

were missing. I tried to do implement them in analogy to the corresponding 2D/3D case.

Some tests are still missing.

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 82.08955% with 12 lines in your changes missing coverage. Please review.

Project coverage is 96.91%. Comparing base (4785741) to head (b394034).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
src/solvers/dgsem_p4est/dg_3d.jl	56.00%	11 Missing ⚠️
src/callbacks_step/analysis_dg2d.jl	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2308      +/-   ##
==========================================
+ Coverage   96.90%   96.91%   +0.01%     
==========================================
  Files         503      505       +2     
  Lines       41717    41768      +51     
==========================================
+ Hits        40425    40479      +54     
+ Misses       1292     1289       -3     

Flag	Coverage Δ
unittests	96.91% <82.09%> (+0.01%)	⬆️

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[amrueda]

Thanks for adding this @benegee!
I have only checked the 2D part, and I think that I identified an issue. I'll commit a suggestion. After this, we can add a test to check if the parallel implementation does the same as the serial one.
@benegee, can you please copy one of the existing curvilinear non-conservative examples into the MPI test suit? (see, e.g., the 3D non-conservative MPI PR: #2126)

[benegee]

I added an MPI test, using a new elixir adapted from the 3D elixir_mhd_alfven_wave_nonconforming.jl.
Would you want to run this without MPI as well, to check consistency?

[amrueda]

I added an MPI test, using a new elixir adapted from the 3D elixir_mhd_alfven_wave_nonconforming.jl. Would you want to run this without MPI as well, to check consistency?

Yes, I think that we should have tests with and without MPI running the same elixir and getting the same reference values. You can just copy a non-conservative test set from test/test_mpi_p4est_2d.jl into test/test_p4est_2d.jl or the other way around 😉

[benegee]

The 2D test cases seem to work.

Any idea which elixir could be used to cover the 3D calc_boundary_flux?