1. fix(perf): Run CPU-intensive state updates in parallel rayon threads

[teor2345]

Motivation

We want to improve Zebra's sync speed to avoid test timeouts in CI (#4155).

This PR moves CPU-intensive verification in state updates to the rayon thread pool.

Close #4790

Partially addresses #4583

Depends-On: #4199
Depends-On: #4795

Specifications

https://docs.rs/rayon/latest/rayon/fn.in_place_scope_fifo.html

Solution

• Run CPU-intensive chain validation and updates in parallel rayon threads
  • Run non-finalized validation and Chain updates in parallel
  • Run non-finalized sprout, sapling, and orchard tree updates and roots in parallel
  • After a non-finalized chain fork, do note commitment and history tree rebuilds in parallel
  • Run finalized sprout, sapling, and orchard tree updates and roots in parallel

Other performance improvements:

• Wrap HistoryTree in an Arc in the state
• Skip generating unused interstitial Sprout treestates

Related changes:

• Remove redundant checks for empty shielded data

Test fixes:

• Improve anchor validation debugging and error messages
• Work around a test data bug, and save some CPU during tests

Review

Anyone can review this PR, it's urgent because CI is failing, and it blocks a release.

Reviewer Checklist

• Code implements Specs and Designs
• Tests for Expected Behaviour
• Tests for Errors

Follow Up Work

• Move database block and transaction fetches to a dedicated blocking and CPU-heavy thread #4788

[codecov]

Codecov Report

Merging #4802 (0baebfc) into main (7b1d452) will decrease coverage by 0.25%.
The diff coverage is 74.34%.

@@            Coverage Diff             @@
##             main    #4802      +/-   ##
==========================================
- Coverage   78.87%   78.61%   -0.26%     
==========================================
  Files         305      306       +1     
  Lines       38169    38362     +193     
==========================================
+ Hits        30104    30159      +55     
- Misses       8065     8203     +138     

[conradoplg]

Looks good, I was a bit confused with a refactoring and I added some documentation suggestions to hopefully make it clearer

[teor2345]

Sorry, I forgot to push the commits for:
- Run non-finalized sprout, sapling, and orchard tree updates and roots in parallel
- After a non-finalized chain fork, do note commitment and history tree rebuilds in parallel
- Some minor cleanups

[teor2345]

I fixed some doc issues and added your suggestions, this is ready for another review.