add a basic test of prjxray.util.get_row().gen_sites()
add a basic test of prjxray.util.get_row().gen_sites()

Signed-off-by: Alon <381dc42aa497421c656ac95e6bb474c5318e600b@pobox.com>

SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray,SymbiFlow/prjxray