This ensures we don't lose races that occur in subprocesses or
interleave races from workers running in parallel.
Log files are collected and packaged into a zipfile that can be
downloaded from the "Artifacts" section of the workflow run.
Additionally, reduce the iterations for a few weakref tests that would
otherwise take a prohibitively long amount of time (> 1 hour) when TSAN
is enabled and the GIL is disabled.
