Move old Mistral benchmarks to own subdirectory

...ks/mistral/LOG.benchmark_2d.run.32394761.o_keep4reference

...ks/mistral/LOG.benchmark_2d.run.32398022.o_keep4reference

...ks/mistral/LOG.benchmark_3d.run.32394974.o_keep4reference

...ks/mistral/LOG.benchmark_3d.run.32398032.o_keep4reference

...ks/mistral/LOG.benchmark_3d.run.32401555.o_keep4reference

...ks/mistral/LOG.benchmark_3d.run.32401557.o_keep4reference

...mark_3d_R10000m-10timesteps.run.32408241.o_keep4reference

...al/LOG.benchmark_cubulation.run.32394751.o_keep4reference

benchmarks/mistral/benchmark_2d.py

benchmarks/mistral/benchmark_2d.run

benchmarks/mistral/benchmark_3d.py

benchmarks/mistral/benchmark_3d.run

benchmarks/mistral/benchmark_3d_R10000m-10timesteps.py

benchmarks/mistral/benchmark_3d_R10000m-10timesteps.run

benchmarks/mistral/benchmark_3d_R10000m-singletimestep.py

benchmarks/mistral/benchmark_3d_R10000m-singletimestep.run

benchmarks/mistral/benchmark_cubulation.py

benchmarks/mistral/benchmark_cubulation.run

benchmarks/mistral/benchmark_cubulation.txt