test for div.sv can fail if RESULT_WIDTH < INPUT_WIDTH

[catkira]

This happens for example for the settings

RESULT_WIDTH = 16
INPUT_WIDTH = 32 
numerator = 3698210746
denominator = 9845

-> https://github.com/catkira/open5G_rx/tree/div_bug
I think it its not so urgent/relevant for the receiver, because in atan2.sv, which is the only place where div.sv is used, RESULT_WIDTH = INPUT_WIDTH. Nevertheless it should be handled in some way. Moreover, the test currently fails only sometimes, because test values are chosen randomly without a fixed seed.