fix(storage): Fix wrong update to the best_block_tips_cache

[msbrogli]

Motivation

The tests/simulation/test_simulator.py::SyncV2RandomSimulatorTestCase::test_many_miners_since_beginning was flaky because of this issue.

When the consensus algorithm updates the best_block_tips_cache, it does not include the current block being evaluated. Notice that the current block is not part of the heads.

Acceptance Criteria

1. Include block to the list of best block tips used to update the best_block_tips_cache.
2. In the assertTipsEqualSyncV2(), we shouldn't assert b1 == b2 because the height index keeps its previous entry when two or more blocks have the same score. So we can safely just check if b1 in s1 and b2 in s2.
3. Notice that, when len(s1) == len(s2) == 1, checking if b1 in s1 and b2 in s2 is exactly the same as checking if b1 == b2.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[msbrogli]

Should we just set to None and let the next call cache it?

[jansegre]

Either way is fine for me. I wish we can get rid of this cache in the future. Will we even need it if we don't have best block ties, because even for sync-v1 the block height index would have a ready O(1) (or at least however fast best_blocks[-1] is) response?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (090bd71) 85.42% compared to head (31c98fb) 85.20%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #874      +/-   ##
==========================================
- Coverage   85.42%   85.20%   -0.23%     
==========================================
  Files         281      281              
  Lines       22353    22355       +2     
  Branches     3388     3388              
==========================================
- Hits        19096    19048      -48     
- Misses       2582     2622      +40     
- Partials      675      685      +10     

Files	Coverage Δ
hathor/consensus/block_consensus.py	95.15% <100.00%> (+0.73%)	⬆️

... and 9 files with indirect coverage changes

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