[ot-font] Fix short-offset calculation

src/hb-ot-font.cc

diff --git a/src/hb-ot-font.cc b/src/hb-ot-font.cc
index f5bf6cc..9cde838 100644
--- a/src/hb-ot-font.cc
+++ b/src/hb-ot-font.cc
@@ -140,8 +140,8 @@
     unsigned int start_offset, end_offset;
     if (this->short_offset)
     {
-      start_offset = this->loca->u.shortsZ[glyph];
-      end_offset   = this->loca->u.shortsZ[glyph + 1];
+      start_offset = 2 * this->loca->u.shortsZ[glyph];
+      end_offset   = 2 * this->loca->u.shortsZ[glyph + 1];
     }
     else
     {