Add very basic afinet socket tests which I started to write in order
to then try to reproduce a kernel panic, which turned out to be a
race condition and hard to test from here.

Commit the changes anywhere as the "bind zero" case was a surprise
to me and we should try to maintain this status.

Also it is easy examples someone can build upon.

With help from: markj
Event: Waterloo Hackathon 2019