37e4cd5faa
bounded_probe_run collapses spawn failure and timeout into one None, so a venv
interpreter that exists but cannot be executed (PermissionError, ENOEXEC, fork
failure) was reported as "timed out before reporting import health" -- a bogus
warning on the git path and sys.exit(1) on the ZIP path -- and the
`except OSError: return {}` branch beneath it was dead. Let the Popen error
propagate (opt-in flag, default unchanged for the other probes) so "we could not
run our own probe" says nothing about the checkout and no longer blocks the
update, while a spawned child that hangs is still a verdict.
Restores the non-fatal test the earlier rewrite dropped, now driving the real
bounded_probe_run/Popen: red on the previous head, green here.
Review finding: spawn failure of the import probe reported as a fatal timeout.