Changes

tests/vty: Show bug inserting routes with different priority

route lookup ((hmrt_message_for_routing() => osmo_ss7_route_lookup() =>
osmo_ss7_route_find_dpc_mask())) iterates the list of routes assuming they are
ordered by mask length (so it doesn't need to iterate the full list every
time). Similary, it implicitly seems to assume that the entries are also
sorted by priority.

However, priority is not currently taken into account when being
inserted in the routing table, so the route ends up in the incorrect
place.

This commit adds a VTY test showing the wrong insert.

Related: SYS#7112
Change-Id: I125046fcbc7563c3275f42ff9de2aa351ae616c1