[Bro-Dev] Failing unit test

[Siwek, Jonathan Luke]

>  language.when … failed

> Is that a race condition with the DNS lookup?

Yeah, looks like the `when` condition should always get evaluated when Bro terminates, but just sometimes the lookup has finished and sometimes it hasn't.  For the purpose of the test, maybe just run the bro instance with `btest-bg-run` and the listen script loaded so it blocks, then call `terminate()` in the body of the `when`.

    Jon