perf: forge fuzz/invariant benches

[0xMelkor]

Motivation

Propose a way to benchmark fuzz/invariant tests in forge (solves #3411)

Solution

• Provide a /benches folder inside the forge crate
• Benchmark the MultiContractRunner struct
• Measure performance against challenging solidity contracts (see Feedback on fuzzer benchmarking setup #4590)

Open points

• Should we use forge/test/it/test_helpers to instantiate MultiContractRunner inside benches ?
• Should we place new solidity tests inside ./testdata/ ?

[0xMelkor]

Hi guys,

reading at discussions on this topic #999 #744 #4590 I think that the approach proposed in this PR does not meet the general requirement.

We don't need to measure blind execution performances, but instead:

• Extend the configurability of the fuzz/invariant runner (i.e. to execute in a provided time window).
• Return aggregated statistics at the end of the process.

The ability to benchmark the Forge runner against similar tools is just a consequence of the points above.

Closing this PR