fix: disable failure persistance in nargo test fuzzing

[asterite]

Description

Problem

Running nargo test with fuzz tests outputs

proptest: FileFailurePersistence::SourceParallel set, but no source file known

which is just noise.

Summary

To reproduce, have a project with this file:

# src/main.nr
#[test]
fn one(_input: u8) {}

Run nargo test. You get:

[one] Running 1 test function
proptest: FileFailurePersistence::SourceParallel set, but no source file known
[one] Testing one... ok
[one] 1 test passed

With this PR:

[one] Running 1 test function
[one] Testing one... ok
[one] 1 test passed

Additional Context

It seems the default failure persistence is a directory called "proptest-regressions". But even when that directory exists we get the error. I assume here that nargo test never produces proptest regressions and that this PR doesn't break things.

Also, it seems test fuzzing in noir is an undocumented feature?

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]

Peak Memory Sample

Program	Peak Memory
keccak256	78.17M
workspace	122.09M
regression_4709	294.72M
ram_blowup_regression	2.44G
private-kernel-tail	208.77M
private-kernel-reset	861.45M
private-kernel-inner	307.68M
parity-root	174.42M

[github-actions]

Compilation Sample

Program	Compilation Time	%
sha256_regression	0m1.522s	7%
regression_4709	0m1.529s	1%
ram_blowup_regression	0m16.779s	1%
private-kernel-tail	0m1.305s	4%
private-kernel-reset	0m8.783s	2%
private-kernel-inner	0m2.673s	13%
parity-root	0m1.128s	8%
noir-contracts	2m48.998s	1%

[michaeljklein]

LGTM