fix(nano): clean up mempool after reorg

[glevco]

Motivation

Clean up NC txs that became invalid after a reorg, removing them from the mempool.

Acceptance Criteria

• Move compute_vertices_that_became_invalid from TransactionStorage to the consensus and change its algorithm:
  • Before, it iterated over all mempool txs with a BFS, executing the reward lock verification for each of them, and marking them to removal if they're invalid.
  • Now, it does a BFS from right to left looking for the rightmost confirmed txs, and starting from those it does a BFS from left to right to find the lefmost invalid txs. Finally, all txs that are right to those are marked for removal. This makes sure blocks are included, at the cost of one extra BFS over the mempool. It also prevents having to run verifications for all txs (since now it marks reverse dependencies for removal, too) which is good because we'll be adding more verifications to this, such as from Nano.
• Refactor consensus, moving invalidation of NC txs to inside compute_vertices_that_became_invalid. Also, that function was called only when the best height decreased, but now it's called for every reorg.

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

[github-actions]

Bencher Report

Branch	fix/nano/clean-up-mempool
Testbed	ubuntu-22.04

Click to view all benchmark results

Benchmark	Latency	Benchmark Result minutes (m) (Result Δ%)	Lower Boundary minutes (m) (Limit %)	Upper Boundary minutes (m) (Limit %)
sync-v2 (up to 20000 blocks)	📈 view plot 🚷 view threshold	1.87 m (+10.88%) Baseline: 1.69 m	1.52 m (81.17%)	2.02 m (92.40%)

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[codecov]

Codecov Report

❌ Patch coverage is 98.41270% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 85.88%. Comparing base (d866f0c) to head (b234b33).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
hathor/consensus/consensus.py	98.41%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1409      +/-   ##
==========================================
+ Coverage   85.86%   85.88%   +0.01%     
==========================================
  Files         432      432              
  Lines       32760    32791      +31     
  Branches     5102     5112      +10     
==========================================
+ Hits        28129    28162      +33     
+ Misses       3610     3609       -1     
+ Partials     1021     1020       -1     

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