sync polytropic benchmark and fix coolddown bug in build_hydrostatic_* scripts
setting 1.0 for the ASPH ratio for planet building
	modified:   build_hydrostatic_core_mantle_planet.py
	modified:   build_hydrostatic_single_layer_planet.py
modified:   build_hydrostatic_core_mantle_planet.py
modified:   build_hydrostatic_single_layer_planet.py
recomputing nbGlobalNodes inside cooldown function