remove test-cases too large for nightly testing

benchmarks/3d_large/It3003.pos

benchmarks/3d_large/It3xxx.geo

benchmarks/3d_large/PTE.geo

benchmarks/3d_large/Senzor.geo

benchmarks/3d_large/Wingmesh.geo

benchmarks/3d_large/buildings_prismmesh.geo

benchmarks/3d_large/buildings_tetmesh.geo

benchmarks/3d_large/bump3d.geo

benchmarks/3d_large/bump_contour.geo

benchmarks/3d_large/choi.geo

benchmarks/3d_large/gasdis.geo

benchmarks/3d_large/layers.geo

benchmarks/3d_large/layers_test_aniso.geo

benchmarks/3d_large/magnetron/README.txt

benchmarks/3d_large/magnetron/box-old.geo

benchmarks/3d_large/magnetron/box.geo

benchmarks/3d_large/magnetron/cylindric.geo

benchmarks/3d_large/magnetron/forme1-old.geo

benchmarks/3d_large/magnetron/forme1.geo

benchmarks/3d_large/magnetron/forme2.geo