Drops two tests that try to monkeypatch a classmethod, which breaks due
to changes in Python 3.9. The project isn't really that well maintained
anymore and Debian started dropping those two tests in November 2020, so
let's follow suit
The `buildPython*` function computes name from `pname` and `version`.
This change removes `name` attribute from all expressions in
`pkgs/development/python-modules`.
While at it, some other minor changes were made as well, such as
replacing `fetchurl` calls with `fetchPypi`.
