Use -q flag when launching Julia

[topolarity]

As of 1.13+, -q will suppress logging output from Julia, not just suppress the start-up banner.

In particular, this prevents notices from the loading system about any (serial) precompilation (see JuliaLang/julia#61064) from clogging stderr (as requested by @vtjnash).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.47%. Comparing base (d439c24) to head (42c078d).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #183   +/-   ##
=======================================
  Coverage   79.47%   79.47%           
=======================================
  Files          10       10           
  Lines        1959     1959           
=======================================
  Hits         1557     1557           
  Misses        402      402           

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[JamesWrigley]

Ehhh I don't think that's a good idea, knowing that something is being precompiled is very useful information, especially on clusters. Is this just for the Julia tests? If so, could they pass -q in the exeflags?

[topolarity]

@vtjnash seems to be concerned that will have behavioral consequences (JuliaLang/julia#61064 (review)):

Can you at least make sure Distributed and Test add the flag, so we don't get regressions in PkgEval or HPC startup behaviors?

I don't know enough about Distributed to have an opinion personally (I just want to get these messages back for normal users)