Debug hgutils flakiness 2/2

As this timeout is more than the harcoded one second in the clone function. That must be the reason why now this is always working.

Test Plan

tox happy

$ pytest -x -s swh/ -k test_clone_timeout --pdb
============================================================================================================= test session starts =============================================================================================================
platform linux -- Python 3.7.3, pytest-6.0.1, py-1.9.0, pluggy-0.13.1
rootdir: /home/tony/work/inria/repo/swh/swh-environment/swh-loader-mercurial, configfile: pytest.ini
plugins: xdist-1.32.0, celery-4.4.6, testinfra-5.2.1, postgresql-2.4.0, django-test-migrations-1.1.0, forked-1.2.0, asyncio-0.12.0, requests-mock-1.8.0, mock-3.1.1, dash-1.13.1, cov-2.11.1, django-3.9.0, flask-1.0.0, hypothesis-6.8.9, redis-2.0.0, kafka-0.4.0, swh.core-0.14.3, swh.journal-0.8.0
collected 54 items / 53 deselected / 1 selected

swh/loader/mercurial/tests/test_hgutil.py 2021-07-28 14:58:48.330530+00:00 start
2021-07-28 14:58:48.334477+00:00 start
2021-07-28 14:58:48.340472+00:00 clone start
(false clone) 2021-07-28 14:58:48.341286+00:00 Sleep for 10 seconds.
2021-07-28 14:58:49.339832+00:00 joined
2021-07-28 14:58:49.340149+00:00 process still alive
2021-07-28 14:58:49.340347+00:00 sleep 0.1 second
2021-07-28 14:58:49.440839+00:00 sleep 0.1 second
2021-07-28 14:58:49.541282+00:00 sleep 0.1 second
2021-07-28 14:58:49.641692+00:00 sleep 0.1 second
2021-07-28 14:58:49.742027+00:00 sleep 0.1 second
2021-07-28 14:58:49.842385+00:00 sleep 0.1 second
2021-07-28 14:58:49.942873+00:00 sleep 0.1 second
2021-07-28 14:58:50.043386+00:00 sleep 0.1 second
2021-07-28 14:58:50.143892+00:00 sleep 0.1 second
2021-07-28 14:58:50.244335+00:00 sleep 0.1 second
2021-07-28 14:58:50.344789+00:00 process 16943 to stop: killed==True

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Migrated from D6041 (view on Phabricator)