Change how we do polygon count in main drc

[atorkmabrains]

@proppy has the following proposal:

logger.info("Total no. of polygons: #{ layers.map { |l| polygons(l).count() }.sum }")
and it currently display an higher level of polygon count for me (1053661) than the currently polygons_count logic (891613) for the caravel_user_project's user_proj_example gds for gf180mcu.