Benchmarks sometimes fail with time out error

[robinhundt]

See https://github.com/robinhundt/CryProt/actions/runs/21457501343/job/61801905588

[dartdart26]

I noticed that and passing -- --test-threads=1 fixes it for me. Maybe something to do with local port assignments?

I will spend some time trying to figure it out and report back if I find something.

[robinhundt]

I think I managed to fix the issue in #105. At least the tests are not failing anymore on macos without test-threads=1. Hopefully this also resolves the intermittent benchmark failures.

EDIT: It seems I celebrated too early. There are still occasional test failures on macos.