By THÉRÈSE MARGOLIS     In a whirlwind tour of the United States, Argentina, Brazil and Mexico last week, Japanese Foreign Minister Taro Kono made it clear to his Mexican counterpart, Luis Videgaray, that despite the current stagnation of the trilateral renegotiations of the North American Free Trade Agreement (NAFTA), his government is committed to maintaining and broadening commercial and economic ties with Mexico. Kono,