Revert "Round when scaling values"

This reverts commit 10f964623f.

See discussion with Khaled Hosny on mailing list.  In short, since
integers here can be negative, and int division is "round towards
zero", proper rounding should take sign into account.  Just skip
doing it again, has been serving us well before.

TODO

@@ -12,6 +12,8 @@ General fixes:
 - Warn at compile time (and runtime with HB_DEBUG?) if no Unicode / font
   funcs found / set.
 
+- Do proper rounding when scaling from font space?  May be a non-issue.
+
 - Misc features:
   * init/medi/fina/isol for non-cursive scripts
 

src/hb-font-private.hh

@@ -397,11 +397,7 @@ struct hb_font_t {
   }
 
   private:
-  inline hb_position_t em_scale (int16_t v, int scale)
-  {
-    unsigned int upem = face->get_upem ();
-    return (v * (int64_t) scale + upem / 2) / upem;
-  }
+  inline hb_position_t em_scale (int16_t v, int scale) { return v * (int64_t) scale / face->get_upem (); }
 };
 
 #define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS