All acts, motions, proceedings, resolutions, and ordinances heretofore passed or adopted by the council of any city and incorporated towns in the state on the supposition that the mayor was not a member of such council, and which would conform to the law if the mayor had not been a member of said council, shall for all purposes from the date of such act, motion, proceeding, resolution, or ordinance, be considered as valid and legal as they would have been had the mayor not been a member of such body.