Disable parent keepalived check and oom score adjustment in test mode

[simu]

Summary

We don't need to check for a keepalived parent process or adjust our own OOM score when running the self-test. This change should allow running the Floaty self-test as a non-root user as long as that user can access the Floaty config file.

Extracted from #92

Checklist

• Keep pull requests small so they can be easily reviewed.
• Categorize the PR by setting a good title and adding one of the labels:
  bug, enhancement, documentation, change, breaking, dependency
  as they show up in the changelog
• Update the documentation.
• Link this PR to related issues.