Integrate ouroboros-consensus for node-8.11.0 (SRP)

[Lucsanszky]

Changelog

- description: |
    Fixed typo in `--ref-script-cost-per-byte` help.
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  # - breaking       # the API has changed in a breaking way
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  # - improvement    # QoL changes e.g. refactoring
  # - bugfix         # fixes a defect
  # - test           # fixes/modifies tests
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Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[smelc]

Superseded by #761

[github-actions]

This PR is stale because it has been open 45 days with no activity.

[carbolymer]

Closing as the changes were already integrated