adds file env_bench for setting compilation environment for code Smilei on Irene-amd

Smilei/machines/irene-amd/env_bench

+#machine file for Irene Joliot-Curie using AMD-ROME
+# __________________________________________________________
+#
+# Load the correct modules:
+#
+module purge
+module load intel/19.0.5.281
+module load mpi/intelmpi/2019.0.5.281
+module load flavor/hdf5/parallel
+module load hdf5/1.8.20
+module load python3/3.7.2
+
+export CXXFLAGS+="-xHOST -axAVX -O3 -ip -inline-factor=1000 -qopt-zmm-usage=high "
+
+GIT_ROOT=`git rev-parse --show-toplevel`
+SMILEI_DIR=$GIT_ROOT/Smilei/
+EXE=$SMILEI_DIR/Smilei/smilei
+
+