Test failed time to time, let's try this way:
```
$ for x in $(seq 1 20); do cp test_bgp_labeled_unicast_addpath.py test_$x.py; done
$ sudo pytest -s -n 20
```
Ran 10 times using this pattern, no failure 🤷
Before this change, we checked advertised routes, and at some point `=` was
missing from the output, but advertised correctly. Receiving router gets as
much routes as expected to receive.
I reversed checking received routes, not advertised.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Check if we advertise more routes when an additional path comes up, and
if we withdraw if dissapears.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>