test_asyncio hangs on "AMD64 Windows7 SP1 3.x" buildbot:
http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.x/builds/5562

The most significant change of this build is the changeset d3804307cce4: "IocpProactor.close() must not cancel pending _WaitCancelFuture futures".

[391/391] test_asyncio
Timeout (1:00:00)!
Current thread 0x000013f8 (most recent call first):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 617 in _unregister
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 193 in _unregister_wait_cb
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 209 in _unregister_wait
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 152 in set_result
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 671 in _poll
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\windows_events.py", line 386 in select
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\base_events.py", line 1081 in _run_once
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\base_events.py", line 258 in run_forever
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\asyncio\base_events.py", line 286 in run_until_complete
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\test_asyncio\test_events.py", line 1695 in test_subprocess_stderr_redirect_to_stdout
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\case.py", line 577 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\case.py", line 625 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\unittest\runner.py", line 168 in run
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\support\__init__.py", line 1770 in _run_suite
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\support\__init__.py", line 1804 in run_unittest
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 1283 in test_runner
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 1284 in runtest_inner
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 967 in runtest
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 532 in main
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 1568 in main_in_temp_cwd
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\regrtest.py", line 1593 in <module>
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\runpy.py", line 85 in _run_code
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\runpy.py", line 170 in _run_module_as_main