tests: fixed config tests locking up on error, added test for predict

The config tests locked up on error as if error was raised from the
event callback, it would never reach the `quit()` statement, so
server would never close on error.

Added a script to make running these types of tests a little bit nicer
and to allow concurrent execution of config tests.

Added a test for the predict module, that fails on prediction
of unknown types:

```
error: /usr/local/lib/kdns_modules/predict.lua:34: 'struct rr_type' has no member named 'TYPE65535'
```