* test: count a zombie grandchild as gone in the migrate deploy timeout test
A SIGKILLed grandchild whose parent died in the same killpg reparents to
PID 1 or the nearest subreaper and stays a zombie until reaped, and signal 0
still succeeds on a zombie, so the timeout test read it as alive wherever
PID 1 is slow to reap or never does. The sibling test in
tests/test_litellm/proxy/db already handled that; both now share one
process_is_gone helper that reads the /proc state and reaps its own
children, with unit tests for the live, reaped, unreaped, and foreign
zombie shapes.
* test: move the pre-commit interrupt test onto the shared zombie-aware liveness helper
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Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
