You can run the test manually (i.e. julia tests/runtest.jl) and you can launch your own sub process with a different option. I’m pretty sure it was there (and probably still is) for the base bounds check test. The file you linked should have been the file run by the subprocess.
Edit: yes, ref https://github.com/JuliaLang/julia/blob/c44644442949238da70670b547312ca1ae9a9c7d/test/boundscheck.jl