tests: add conditional output when simplestore extensions is loaded This drops the number of failures with this extension to 3. Differential Revision: https://phab.mercurial-scm.org/D4286

tests: conditionalize extension tests for extra extensions If extra extensions are loaded (e.g. via --extra-config-opt), the tests conditionalized in this commit fail in ways that are dependent on the extensions that are loaded. So let's skip them when that scenario is present. This drops the number of failures for the simplestorerepo.py extension to 4. Differential Revision: https://phab.mercurial-scm.org/D4285