Fix stack overflow in debug mode

[elmattic]

Summary of changes

Changes introduced in this pull request:

• Fix stack overflow occurring when running Forest in debug mode

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

[LesnyRumcajs]

What's precisely causing the SO?

Ah okay, we recursively call the mark_bad_tipset

[LesnyRumcajs]

LGTM, but let's wait for the seal of approval from @lemmih before merging.

[lemmih]

Sigh, my love of recursion comes to haunt me.