Add test_handle_router_snat_rules_add_rules
Add test_handle_router_snat_rules_add_rules

Add a unit test to verify that snat rules are added and added in order.
So that it could be refactored without fear next time.

Closes-Bug: #1222660
Change-Id: I07e820cc28c9a6c139a8eed0917aef2cfe62638a

gkotton/vmware-nsx,gkotton/vmware-nsx