[DRT] Reduce frMaster memory usage
[DRT] Reduce frMaster memory usage

name2term is only used once during design import and isn't worth maintaining.

Signed-off-by: Austin Rovinski <fcf2266bfbf73692490c0038f6d4290540d21769@umich.edu>

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