[skip ci] Use a real unstructured grid for the test

...poisson/facedir-facemod-variation/grid_transformed_24.msh

...poisson/facedir-facemod-variation/grid_transformed_25.msh

...poisson/facedir-facemod-variation/grid_transformed_26.msh

...poisson/facedir-facemod-variation/grid_transformed_27.msh

...poisson/facedir-facemod-variation/grid_transformed_28.msh

...poisson/facedir-facemod-variation/grid_transformed_29.msh

...poisson/facedir-facemod-variation/grid_transformed_30.msh

...poisson/facedir-facemod-variation/grid_transformed_31.msh

...poisson/facedir-facemod-variation/grid_transformed_32.msh

...poisson/facedir-facemod-variation/grid_transformed_33.msh

...poisson/facedir-facemod-variation/grid_transformed_34.msh

...poisson/facedir-facemod-variation/grid_transformed_35.msh

...on/poisson_dg_gmsh_3d_facedir_facemod_variation_driver.cc

...tion/sumfact_poisson_dg_3d_facedir_facemod_variation.mini

...sumfact_poisson_dg_3d_facedir_facemod_variation_driver.cc