There is PYBUILD_DISABLE_pypy=test, it would be nice to also have
PYBUILD_IGNORE_pypy=test to run and ignore the results. A use case would be e.g.
to document test results, but not to fail the package build. E.g. I might be
interested in python2.7 packages as long as I have to, but maybe don't want to
block an upload for a package that might be removed in the near future.