[face] Return nil face if blob is inert

src/hb-font.cc

@@ -379,6 +379,9 @@ hb_face_t *
 hb_face_create_for_data (hb_blob_t    *blob,
 			 unsigned int  index)
 {
+  if (unlikely (hb_object_is_inert (blob)))
+    return &_hb_face_nil;
+
   hb_face_for_data_closure_t *closure = _hb_face_for_data_closure_create (Sanitizer<OpenTypeFontFile>::sanitize (hb_blob_reference (blob)), index);
 
   if (unlikely (!closure))