That function is nose specific and has not worked since `__init__` files
were added to the tests directories.

These tests were not included in the `setup.py` file and consequently
not available in the installed numpy for testing.

This allows pytest to run with duplicate test file names. Note that
`python <path-to-test-file>` no longer works with this change, nor will
a simple `pytest numpy`, because numpy is imported from the numpy
repository. However, `python runtests.py` and `>>> numpy.test()` are
still available.

The aim here is to separate out the nose dependent files prior to adding
pytest support. This could be done by adding new files to the general
numpy/testing directory, but I felt that it was to have the relevant
files separated out as it makes it easier to completely remove nose
dependencies when needed.

Many places were accessing submodules in numpy/testing directly, and in
some cases incorrectly. That presented a backwards compatibility
problem. The solution adapted here is to have "dummy" files whose
contents will depend on whether of not pytest is active. That way the
module looks the same as before from the outside.

In the case of numpy itself, direct accesses have been fixed. Having
proper `__all__` lists in the submodules helped in that.

Use the full module path when importing importlib.machinery for use in the
npy_load_module function. Just importing importlib is not sufficient in certain
cases, for example Python 3.4.

closes #8147

Some newer *.py files are missing the `from __future__` boilerplate
that helps assure Python2 and Python3 compatibility.

allows passing flags like --pdb to test files
also add call to files where its missing