Revert "[ot-lang] Use atomic int for cache"

This reverts commit d61b207491.

src/hb-ot-tag.cc

@@ -297,13 +297,13 @@ hb_ot_tags_from_language (const char   *lang_str,
 
     hb_tag_t lang_tag = hb_tag_from_string (lang_str, first_len);
 
-    static hb_atomic_int_t last_tag_idx; /* Poor man's cache. */
-    unsigned tag_idx = last_tag_idx.get_relaxed ();
+    static unsigned last_tag_idx; /* Poor man's cache. */
+    unsigned tag_idx = last_tag_idx;
 
     if (likely (tag_idx < ot_languages_len && ot_languages[tag_idx].language == lang_tag) ||
 	hb_sorted_array (ot_languages, ot_languages_len).bfind (lang_tag, &tag_idx))
     {
-      last_tag_idx.set_relaxed (tag_idx);
+      last_tag_idx = tag_idx;
       unsigned int i;
       while (tag_idx != 0 &&
 	     ot_languages[tag_idx].language == ot_languages[tag_idx - 1].language)