In Cook County Associate Judge Patricia Mendoza’s courtroom there is a dress code.But instead of asking juvenile defendants to buy their own collared shirts, ties, dress pants, skirts or dresses — if they don’t own such items already — Mendoza already has it taken care of.When a defendant is arraigned, Mendoza informs them of the dress code and tells them to let their attorney know if they do not have their clothing suitable for court.If that’s the case, Mendoza tells the attorney, or in some …