One choir concert almost made time stand still, another set history in motion during Oslo International Church Music Festival. There are seldom that many, and that good, choirs in this country as during the church music festival in Oslo. It is especially thrilling to encounter foreign ensembles in a repertoire and style clearly distinguished by the areas they come from.  The audience has had an infatuation for a particular tradition for some time and that filled Oslo Cathedral to the last bench when Sergey Rachmaninov’s Vesper opus 37 was performed Tuesday.