ipv4/6: fix ignore_nonstatic_routes tests
The tests need to be run without trace logs, otherways it breaks CI. Also, switch to testveth devices, so in any failure scenario, routes should be gone after the test.
Lower the limit to 500 000 in ipv6 case, which is bearable, 2 000 000 is taking 65 minutes. The bugs seems not fixed yet.
Closes #26 (closed)