Due to SO_REUSE_PORT it is possible for a localhost:0
address to repeat. This causes failure in DHT tests
where we spun up a lot of nodes inside test.

As for a birthday paradox it is enough to use 140
ports to get 20% chance for collision which was causing
failure in our case.

The fix is to disable REUSE_PORT routine for the
tests and leave it running for sharness tests where
not that many addresses are used at the same time.

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>