Issue #20452: add more info in case of test_asyncio failure to try to debug the
failure on buildbot "x86 Ubuntu Shared 3.x"
Issue #20452: Oops, fix debug code :-/

Add also event more debug info
Issue #20452: select and selectors round (again) timeout away from zero for
poll and epoll

Improve also debug info to analyze the issue
asyncio: Fix error message in BaseEventLoop.subprocess_shell(). Patch written
by Vajrasky Kok.
Issue #20452: Remove debug code, no more needed
Issue #20311, #20452: poll and epoll now round the timeout away from zero,
instead of rounding towards zero, in select and selectors modules:
select.epoll.poll(), selectors.PollSelector.poll() and
selectors.EpollSelector.poll(). For example, a timeout of one microsecond
(1e-6) is now rounded to one millisecondi (1e-3), instead of being rounded to
zero.

Mention the change in Misc/NEWS.
asyncio: Fix _UnixWritePipeTransport, raise BrokenPipeError when the pipe is
closed, but only if there was pending write