The return of commissions to mark and bound lands, if no action is brought to controvert the same within 7 years, shall be conclusive evidence of the original location of such land, and of the lines and boundaries thereof, saving to infants, persons insane, imprisoned or beyond sea, and those claiming under them, the right to bring such action within 5 years from the removal of such disability. The term of 7 years shall not begin to run against any person while such person is in possession of the land in controversy.