Cleanup: Remove a workaround

Since commit 1bd681c
dict_stats_exec_sql() is no longer playing dirty tricks.
We can remove the workaround in lock_release().

storage/innobase/lock/lock0lock.cc

@@ -3791,11 +3791,7 @@ void lock_release(trx_t *trx)
 #if defined SAFE_MUTEX && defined UNIV_DEBUG
   std::set<table_id_t> to_evict;
   if (innodb_evict_tables_on_commit_debug && !trx->is_recovered)
-# if 1 /* if dict_stats_exec_sql() were not playing dirty tricks */
-    if (!dict_sys.mutex_is_locked())
-# else /* this would be more proper way to do it */
     if (!trx->dict_operation_lock_mode && !trx->dict_operation)
-# endif
       for (const auto& p: trx->mod_tables)
         if (!p.first->is_temporary())
           to_evict.emplace(p.first->id);