Tests don't saturate CPU threads, and can take a while.

[nuke-web3]

Originally posted by @nuke-web3 in #21 (comment)

$ ./scripts/fuzz-test.sh
# nargo export --force-brillig
finished in 12.17s
...
# nargo export
finished in 280.74s

Those tests with nargo export took a long while... I would not have expected that. Anything that could be done to better optimize in this? I notice that seemingly only 2 cores / 4 threads are saturated on my machine (I have 14, most idling while testing).

If the prover can't use all threads, perhaps at least https://nexte.st/ could help make these tests run in parallel.