python zeroc-ice doesn't respect the build_job_number config option
During the initial setup, every time the zeroc-ice python package gets installed in a venv, the setup.py compiles the C++ Ice codebase. But for some reason this only compiles a single compilation unit at a time, needlessly delaying the venv setup on multi-core systems.
Also, since multiple venvs are getting set up during the initial axii workspace upgrade, this compiles the same code multiple times.