Added larger benchmarking model.

tests/benchmarking/bench_450x450x450.in

@@ -0,0 +1,7 @@
+#domain: 0.45 0.45 0.45
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: gaussiandotnorm 1 900e6 MySource
+#hertzian_dipole: x 0.05 0.05 0.05 MySource
+#rx: 0.05 0.05 0.05