[3.6] bpo-31334: Fix timeout in select.poll.poll() (GH-3277)

[miss-islington]

Always pass -1, or INFTIM where defined, to the poll() system call when
a negative timeout is passed to the poll.poll([timeout]) method in the
select module. Various OSes throw an error with arbitrary negative
values.
(cherry picked from commit 6cfa927)

https://bugs.python.org/issue31334

[miss-islington]

@volans- and @Haypo: Backport status check is done, and it's a success ✅ .

[miss-islington]

Thanks, @serhiy-storchaka!