feat: let nargo test use the new greybox fuzzer

[asterite]

Description

Problem

Part of #8214

Summary

Now nargo test will use the new fuzzer. For now:

• The output of the test program (the print and println) calls will never be shown. Previously it did shown with --show-output but, like the first iteration in fix: let nargo test --show-output work for tests with arguments #8206, it showed all output of all runs, which is probably not desired. Given that --show-output didn't work for tests with arguments, this "preserves" that behavior and we can maybe fix it later.
• It uses some default configurations: the default corpus directory, 1 timeout second and 1 thread (I thought about using the same number of threads as what's passed to nargo test but then we'd get more threads than that as nargo test already runs on tests in a thread pool). Given that previously there was no way to configure these when running nargo test I think it's fine to leave these for now and make them configurable in a later PR.

Then, the usual progress shown when running nargo fuzz (all of the "NEW", "LOOP", etc., outout) isn't shown when running nargo test. For example, for this program:

#[test]
fn fuzz(x: i8) {
    assert(x != 10);
}

we get this output:

$ nargo test
[one] Running 1 test function
[one] Testing fuzz ... FAIL
Execution failed: Failed to solve program: 'Cannot satisfy constraint': <no message>
Failing input: {"x":"0x000000000000000000000000000000000000000000000000000000000000000a"}

error: Failed constraint
  ┌─ src/main.nr:3:12
  │
3 │     assert(x != 10);
  │            -------
  │
  = Call stack:
    1. src/main.nr:3:12


[one] Failures:
     fuzz

[one] 1 test failed

For this program:

#[test]
fn fuzz(_: i8) {}

we get this output:

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

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]

⚠️ Performance Alert ⚠️

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

Benchmark suite	Current: 3f16f7e	Previous: ac7a20f	Ratio
rollup-root	1.806 s	1.384 s	1.30

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

CC: @TomAFrench

[Rumata888]

This is great, thank you!