get_tile_infrastructure_set(): Use extra_type_by_rmcause_iterate()
get_tile_infrastructure_set() should use extra_type_by_rmcause_iterate() instead of
extra_type_iterate(pextra) { if (is_extra_removed_by(pextra, ERM_PILLAGE)
get_tile_infrastructure_set() should use extra_type_by_rmcause_iterate() instead of
for better performance