drt: fix issue with zero area drc markers
drt: fix issue with zero area drc markers

Boost polygon tends to eliminate zero area polygons during boolean operations
which leads to such markers being lost.

Signed-off-by: Matt Liberty <44ef1ce0ef6935daf739a0795dad249ba5322e97@eng.ucsd.edu>

QuantamHD/OpenROAD,QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD,QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD