[glyf] Add a pre-allocation for phantom points

src/OT/glyf/SimpleGlyph.hh

@@ -158,7 +158,8 @@ struct SimpleGlyph
     if (unlikely (!bytes.check_range (&endPtsOfContours[num_contours - 1]))) return false;
     unsigned int num_points = endPtsOfContours[num_contours - 1] + 1;
 
-    points_.resize (num_points);
+    points_.alloc (num_points + 4); // Allocate for phantom points, to avoid a possible copy
+    if (!points_.resize (num_points)) return false;
     if (phantom_only) return true;
 
     for (int i = 0; i < num_contours; i++)