Don't touch the fortran files, since indentation is signficant there and it makes things more error-prone

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

Use standard pytest markers everywhere in the numpy tests. At this point
there should be no nose dependency. However, nose is required to test
the legacy decorators if so desired.

At this point, numpy test cannot be run in the way with runtests, rather
installed numpy can be tested with `pytest --pyargs numpy` as long as
that is not run from the repo. Run it from the tools directory or some
such.

See #10027.

1. fail tests related to DLL load failure as they were previously untested.
2. fix have_compiler to return false on old compilers
3. xfail some tests that were not working on old Python versions.

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.