[minor] Add unlikely() when checking for error

src/hb-face.cc

diff --git a/src/hb-face.cc b/src/hb-face.cc
index a15687c..900014f 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -756,7 +756,7 @@
   hb_face_builder_data_t *data = (hb_face_builder_data_t *) face->user_data;
 
   hb_face_builder_data_t::table_entry_t *entry = data->tables.push ();
-  if (data->tables.in_error())
+  if (unlikely (data->tables.in_error()))
     return false;
 
   entry->tag = tag;