chore(brillig): Document and test explicit memory limit

[vezenovm]

Description

Problem

Resolves #11200

Check out #11200 (comment) and the preceding discussion for more context. Rust has a fundamental per-allocation isize::MAX limit.

Summary

Changes:

• Clearer panic message instead of "capacity overflow" panic from Rust
• Test displaying this behavior
• Deterministic behavior on 32-bit and 64-bit architectures

Additional Context

To actually fix the auditor's concern in #11200 about being able to use the full u32 address space, we would most likely need chunked memory. In order to bypass Rust's fundamental allocation limit we would need many smaller Vec fields to cover the full address space. I made a follow-up here #11291 for 1.0+, although I find this to be low priority either way as i32::MAX is a practical limit for the time being.

User Documentation

Check one:

• No user documentation needed.
• Changes in docs/ included in this PR.
• [For Experimental Features] Changes in docs/ to be submitted in a separate PR.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'ACVM Benchmarks'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 59754c9	Previous: bb296ff	Ratio
perfectly_parallel_batch_inversion_opcodes	2799589 ns/iter (± 1739)	2269293 ns/iter (± 1033)	1.23

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[aakoshh]

TIL my limits 🙇