[pypy-issue] Issue #2890: missing os.sched* functionality (pypy/pypy)

New issue 2890: missing os.sched* functionality https://bitbucket.org/pypy/pypy/issues/2890/missing-ossched-functionality mattip: Apparently CPython added an interface to the [os scheduler](https://docs.python.org/3/library/os.html#interface-to-the-scheduler) in python 3.3, we lack support for it in posix. Tests in `lib-python/3/test/test_posix.py` are silently skipped, even on linux where it should exist. This turns out is used in [CI testing](https://github.com/scikit-learn/scikit-learn/pull/12039#discussion_r21807430...) to determine how many cpus can be used. Since this means someone is trying to get PyPy into their test matrix, we should try to encourage them.