[GUI] Floating triangles drawn when primitive nets enabled.

[SamuelHo10]

Very small, black floating triangles are drawn when the draw primitive nets option is selected. I think these are supposed to be arrows which lie on the path of the flylines, but they are currently mispositioned.

The command being run is $VTR_ROOT/vpr/vpr \ $VTR_ROOT/vtr_flow/arch/multi_die/koios_3d/3d_full_OPIN_inter_die_k6FracN10LB_mem20k_complexDSP_customSB_7nm.xml \ ode --circuit_file ./ode.pre-vpr.blif \ --route_chan_width 100 \ --analysis --disp on