[graphite] Remove hb_graphite2_feature_check()

I don't see how this function can be useful.

src/hb-graphite2.cc

@@ -433,14 +433,4 @@ dieout:
     return success;
 }
 
-int hb_graphite2_feature_check(const hb_feature_t *feats, unsigned int num_feats)
-{
-    while (num_feats--)
-    {
-        if (feats[num_feats].tag == HB_TAG(' ', 'R', 'N', 'D'))
-            return (feats[num_feats].value == 1);
-    }
-    return 1;
-}
-
 HB_END_DECLS

src/hb-graphite2.h

@@ -40,8 +40,6 @@ hb_bool_t hb_graphite_shape (hb_font_t    *font,
 			unsigned int  num_features,
             const char * const *shaper_options);
 
-int hb_graphite2_feature_check(const hb_feature_t *feats, unsigned int num_feats);
-
 HB_END_DECLS
 
 #endif /* HB_GRAPHITE2_H */