[web/tests] Hide DeprecationWarnings

[web] remove next_tabindex() It's hard to see it work reliably in view of multiple server processes. If something like that is needed it should probably be built on the client (js) side.

[views/optimization] Ensure we call rset.possible_actions with the same argument rset.possible_actions (which should definitly not be an ResultSet method, but that's another story) has been designed to hold a cache to compute possible actions for a only once, since this may be a fairly costly operation (notably because of the 'has_editable_relations' predicates). But this has been broken by introduction of a new 'view' parameter which is not given by every call. To fix this, this cset adds the missing view argument where necessary and reimplements the rset's method to assert it's always called with the same key. Unfortunatly, those changes have to be ported to squareui and bootstrap cubes as well.