MILAN – The United States women’s hockey team will enter the gold medal clash with Canada on Thursday having not given up a single goal since its first game of the tournament.  Behind a stacked forward group and a deep defensive corps, goaltending is just another X factor for Team USA thanks to a trio of goaltenders — Aerin Frankel , Gwyneth Philips and Ava McNaughton — that is new additions to the Olympic squad.  Frankel has started in four of Team USA’s six games so far, stopping 67 of the 68