Add likely/unlikely to speed up execution

Added to:
- if (error)
- Lex
- sql_yacc.yy and sql_yacc_ora.yy
- In header files to alloc() calls
- Added thd argument to thd_net_is_killed()

sql/temporary_tables.cc

@@ -1398,7 +1398,8 @@ bool THD::log_events_and_free_tmp_shares()
 
       get_stmt_da()->set_overwrite_status(true);
       transaction.stmt.mark_dropped_temp_table();
-      if ((error= (mysql_bin_log.write(&qinfo) || error)))
+      bool error2= mysql_bin_log.write(&qinfo);
+      if (unlikely(error|= error2))
       {
         /*
           If we're here following THD::cleanup, thence the connection