Deadlock while creating verifier process

[volhovm]

See the branch volhovm/16112-reproduce-deadlock in mina repo: the first commit, which adds some printing into srs.rs leads to the situation where the test deadlocks. Here's the minimal commit.

eddb06f

It is also reproducible on top of compatible in this branch: volhovm/16112-reproduce-deadlock-from-compatible, again see the first commit in that branch.

Steps to reproduce:

dune build src/app/cli/src/mina.exe && _build/default/src/app/cli/src/mina.exe transaction-snark-profiler --zkapps --k 1 --max-num-updates 4 --min-num-updates 2

I'm suspecting the problem is with printing in particular. Something in the worker-main thread communication layer breaks with printing being done from the rust side earlier. Double checking how the stdout/stderr is handled around rpc would be a good start maybe.