Add a make_no_network_finder() test helper.
Add a make_no_network_finder() test helper.

rouge8/pip,pfmoore/pip,xavfernandez/pip,pypa/pip,pfmoore/pip,pradyunsg/pip,xavfernandez/pip,rouge8/pip,pradyunsg/pip,rouge8/pip,pypa/pip,xavfernandez/pip,sbidoul/pip,sbidoul/pip