feat: avoid unnecessary memory allocation/deallocations in brillig VM

[TomAFrench]

Description

Problem*

Resolves

Summary*

I noticed that we're doing a lot of resizing of the underlying vec when writing to memory. Doing some experimenting.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation 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]

Compilation Report

Program	Compilation Time	%
sha256_regression	1.050s	5%
regression_4709	0.821s	1%
ram_blowup_regression	16.800s	5%
rollup-root	3.554s	-2%
rollup-merge	2.034s	-4%
rollup-block-root-single-tx	138.000s	0%
rollup-block-root-empty	2.050s	-1%
rollup-block-root	138.000s	2%
rollup-block-merge	3.680s	4%
rollup-base-public	28.140s	1%
rollup-base-private	10.068s	-1%
private-kernel-tail	0.971s	-4%
private-kernel-reset	6.202s	2%
private-kernel-inner	2.194s	-1%

[github-actions]

Execution Report

Program	Execution Time	%
sha256_regression	0.051s	-2%
regression_4709	0.001s	0%
ram_blowup_regression	0.600s	-2%
rollup-root	0.104s	0%
rollup-merge	0.006s	-15%
rollup-block-root	36.800s	-1%
rollup-block-merge	0.104s	0%
rollup-base-public	1.225s	-1%
rollup-base-private	0.449s	-2%
private-kernel-tail	0.019s	0%
private-kernel-reset	0.311s	0%
private-kernel-inner	0.069s	1%

[github-actions]

Compilation Memory Report

Program	Peak Memory
keccak256	77.560
workspace	123.770
regression_4709	424.070
ram_blowup_regression	1460.000
rollup-root	601.170
rollup-merge	494.140
rollup-block-root-single-tx	16060.000
rollup-block-root-empty	488.320
rollup-block-merge	601.160
rollup-base-public	2380.000
rollup-base-private	996.420
private-kernel-tail	207.340
private-kernel-reset	584.400
private-kernel-inner	294.600

[github-actions]

Execution Memory Report

Program	Peak Memory
keccak256	74.630
workspace	123.460
regression_4709	424.070
ram_blowup_regression	512.570
rollup-root	498.200
rollup-merge	472.940
rollup-block-merge	498.210
rollup-base-public	734.090
rollup-base-private	996.420
private-kernel-tail	180.820
private-kernel-reset	245.440
private-kernel-inner	294.600

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Execution Memory'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.10.

Benchmark suite	Current: dae4f7c	Previous: df71bde	Ratio
regression_4709	424.07 MB	315.94 MB	1.34
rollup-base-private	996.42 MB	590.4 MB	1.69
private-kernel-inner	294.6 MB	208.84 MB	1.41

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

CC: @TomAFrench