CALGARY, Alberta — Before the Islanders’ 4-2 loss Saturday against the Flames , coach Patrick Roy was asked about something he’d said two days prior: that he keeps waiting for Matthew Schaefer to hit the rookie wall, and it still hasn’t happened. The arc of Schaefer’s rookie season has indeed defied any reasonable expectations. For his fellow rookie Cal Ritchie, a highly touted prospect in his own right, though not with the No. 1 overall pedigree of Schaefer, it’s been a little more