tox: fix handling of flaky tests during CI builds
tox: fix handling of flaky tests during CI builds

xavfernandez/pip,techtonik/pip,pfmoore/pip,pypa/pip,pypa/pip,RonnyPfannschmidt/pip,zvezdan/pip,sbidoul/pip,pfmoore/pip,techtonik/pip,zvezdan/pip,pradyunsg/pip,sbidoul/pip,zvezdan/pip,rouge8/pip,rouge8/pip,xavfernandez/pip,RonnyPfannschmidt/pip,pradyunsg/pip,RonnyPfannschmidt/pip,xavfernandez/pip,techtonik/pip,rouge8/pip