test(dursto): Add roundtrip tests of Normal -> Verify for MAVL tree on structural-change operations.

[NSant215]

Closes RV-963.
Closes RV-961.

What

Adds (currently failing) roundtrip tests on the Prove and Verify modes of the MAVL tree with operations involving structural changes of the tree.

Why

The current design is flawed. These operations need to be infallible.

Manually Testing

make all

Tasks for the Author

• Link all Linear issues related to this MR using magic words (e.g. part of, relates to, closes).
• Eliminate dead code and other spurious artefacts introduced in your changes.
• Document new public functions, methods and types.
• Make sure the documentation for updated functions, methods, and types is correct.
• Add tests for bugs that have been fixed.
• Explain changes to regression test captures when applicable.
• Write commit messages in agreement with our guidelines.
• Self-review your changes to ensure they are high-quality.
• Complete all of the above before assigning this MR to reviewers.

[codecov]

Codecov Report

❌ Patch coverage is 24.66960% with 171 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.23%. Comparing base (9e0aac7) to head (0a81afa).

Files with missing lines	Patch %	Lines
durable-storage/src/avl/resolver.rs	24.66%	163 Missing and 8 partials ⚠️

❌ Your patch check has failed because the patch coverage (24.66%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@               Coverage Diff               @@
##           santnr/mavl     #992      +/-   ##
===============================================
- Coverage        89.70%   89.23%   -0.48%     
===============================================
  Files              125      125              
  Lines            27103    27273     +170     
  Branches         27103    27273     +170     
===============================================
+ Hits             24314    24338      +24     
- Misses            2143     2288     +145     
- Partials           646      647       +1     

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