samples: introduce incomplete_init category

[manuelh-dev]

Merge Checklist

• Followed patch format from upstream recommendation: https://github.com/kata-containers/community/blob/main/CONTRIBUTING.md#patch-format
  • Included a single commit in a given PR - at least unless there are related commits and each makes sense as a change on its own.
• Aware about the PR to be merged using "create a merge commit" rather than "squash and merge" (or similar)
• genPolicy only: Ensured the tool still builds on Windows
• The upstream/missing label (or upstream/not-needed) has been set on the PR.

Summary

Add the new category for tests we want to run genpolicy against, but not run them in deployments (as the name suggests, we cannot run those).

Test Methodology

Ran update_policy_samples.py and observed that the incomplete_init samples would still be processed