[wheels] skip test suite on some platforms
[wheels] skip test suite on some platforms

When there are no binary wheels of numpy, the test suite takes ages to
run because numpy needs to be built from source.

There are no binary wheels of numpy:

- for Python 3.7
- for PyPy on some platforms
- for i686

PyAV-Org/PyAV,PyAV-Org/PyAV