feat(memory): use Vector in PageProtections component

[vapourismo]

What

Replace the boxed array with Vector in the PageProtections component.

Why

This lets us remove the const-generic parameter, which paves the way for making the memory size runtime configurable.

A nice effect of this change is that the memory overhead in Verify mode is reduced quite a bit.

• For 4 GiB of memory at 4 KiB page size, we have 1,048,576 pages
• Atom<bool, Verify> is 33 B
• One PageProtections<Verify> is therefore 33 MiB - regardless of whether it's present, blinded or absent
• We have three permission modes, therefore 3x PageProtections -> 99 MiB unconditionally

The Vector component has a 104 B footprint in Verify mode when it is completely absent.

I am not sure if it's a reference machine glitch, but it looks like there is a +2% TPS bump in it as well.

Manually Testing

make all

Regressions

Using the Vector state component in place of the previous boxed fixed-sized array changes the Merkle tree structure and therefore the hashes and proof serialisation.

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.

[github-actions]

Benchmark results for revision 001c765:

Metric	Duration	TPS
Mean	1.51977489s	26.320
Worst	1.526182235s	26.209
Best	1.51239076s	26.448
Standard Deviation	±4.469717ms	±0.077

Full results

Run	Transfers	Duration	TPS
1	40	1.522589506s	26.271
2	40	1.524376523s	26.240
3	40	1.526182235s	26.209
4	40	1.521771923s	26.285
5	40	1.51239076s	26.448
6	40	1.513750718s	26.424
7	40	1.526021596s	26.212
8	40	1.515477274s	26.394
9	40	1.520050592s	26.315
10	40	1.515755592s	26.389
11	40	1.512877888s	26.440
12	40	1.525150866s	26.227
13	40	1.524128411s	26.245
14	40	1.521559554s	26.289
15	40	1.515578035s	26.393
16	40	1.519430773s	26.326
17	40	1.523642778s	26.253
18	40	1.517234265s	26.364
19	40	1.52201175s	26.281
20	40	1.515516756s	26.394

Compare the results above with those for the default branch.

[codecov]

Codecov Report

❌ Patch coverage is 93.39623% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.90%. Comparing base (6b8df3c) to head (a465155).

Files with missing lines	Patch %	Lines
pvm/src/pvm/linux.rs	81.81%	2 Missing ⚠️
pvm/src/pvm/tezos.rs	75.00%	2 Missing ⚠️
pvm/src/machine_state/memory/protection.rs	96.00%	1 Missing ⚠️
pvm/src/pvm/common.rs	75.00%	1 Missing ⚠️
pvm/src/pvm/linux/signals.rs	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #962      +/-   ##
==========================================
+ Coverage   89.70%   89.90%   +0.19%     
==========================================
  Files         110      110              
  Lines       22136    22132       -4     
  Branches    22136    22132       -4     
==========================================
+ Hits        19857    19897      +40     
+ Misses       1884     1841      -43     
+ Partials      395      394       -1     

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