feat: Handle should_fail_with case

[kevaundray]

Description

resolves #2484 .

I think the code for testing could do with quite a bit of love and refactoring.

Problem*

Resolves

Summary*

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

PR Checklist*

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

[jfecher]

When I run this PR with the code:

#[test(should_fail_with = "f")]
fn foo() {
    assert(false, "fdsa")
}

It still passes, even though I'd expect it to fail.

Edit: Oh I see, we're just testing if the actual message contains the expected message. I didn't expect that but now that I know it makes sense.

[kevaundray]

n though I'd expect it to fail

Just asked Lasse and he would expect that to fail, so I'll change it!

[vezenovm]

Mainly some style suggestions, but non-blocking. It would nice to add nargo test capabilities to our testing suite as well, but that is for a separate PR.