repoview: add more tests to track operation not supposed to trigger filtering This test is useful to confirm we removed filtering trigger and to prevent it to come back without us noticing. The commands tested in the test were initially introduced one by one. However, on Martin von Zweigbergk request, we are adding them all at once. Differential Revision: https://phab.mercurial-scm.org/D7514

localrepo: mark nullrev has never filtered All repository have a null, and it cannot be filtered. Differential Revision: https://phab.mercurial-scm.org/D7484

changectx: add a "maybe filtered" filtered attribute There are changeset that we know not to be filtered (eg: `null`). In this case, we could access some information without triggering changelog filtering. We add an attribute to changectx that track this property. Differential Revision: https://phab.mercurial-scm.org/D7483