[IMP] core: avoid to check access rules on empty recordset

Checking access rules only makes sence if we have some records,
_filter_access_rules will always return a subset or current
recordset, and a subset or a empty recordset is an empty recordset.

closes odoo/odoo#32313

Signed-off-by: Raphael Collet (rco) <rco@openerp.com>