[rset] replace entity cw_rset on .limit(inplace=True) will avoid pb if the entity is still referenced by some other entity relations cache. Closes #2065643 Also, drop '_resultset' from some test names on the way (redundant information, we're in ResultSetTC...)

if schema['TZDatetime'].eid is None:
    add_entity_type('TZDatetime')
if schema['TZTime'].eid is None:
    add_entity_type('TZTime')