Draft: Tezt: test delegators participation calculator

Tests for !17406 (merged)

• Negative tests
  • Cycle too far in the future
  • Cycle too far in the past
  • delegate_pkh is not a delegate
  • delegate_pkh is unknown
  • too old protocol (manual test)
• Positive tests
  • Observables
  • Various stakers and delegators
  • Overdelegation / overstaking
  • Delegate change
  • Multiple delegate changes
  • Min-delegated level cases
  • Protocol migration
  • Manual tests

Manually testing the MR

dune exec tezt/tests/main.exe -- -f tezt/tests/delegators_contribution.ml

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR