Since the commands "locale", "pbpaste" and "pbcopy" are not in nixpkgs,
as they are impure darwin dependencies, we currently cannot get the
clipboard and locale functionality to work properly. We disable the
tests "test_locale" and "test_clipboard" on darwin, so we get a mostly
working pandas. Additionally to disabling the test via py.test, we also
need to provide fake pbpaste/pbcopy commands, so py.test won't fail
during the collection phase.
This closes#25417 and closes#11623.
