In CI / or local testing when you run `serenity.sh tests`, the system
will boot itself in self test mode, and the test runner will be launched
by SystemServer. Previously we were setting up settings for that
environment in the `SystemServer.ini`. This makes reproducing CI
failures a bit confusing, as the system will behavior differently if you
run in self-test mode, vs running `run-tests-and-shutdown.sh` or
`run-tests` manually in a session.
This change moves the settings to `run-tests`, so no matter how you try
to run the test runner, it will always behave the same.
6bf91d00ef