Store instruction id sequence in CFG.

Author: xclerc

backend/regalloc/regalloc_rewrite.ml

@@ -375,7 +375,7 @@ let prelude :
   let critical_edges = compute_critical_edges cfg in
   if not (Cfg_edge.Set.is_empty critical_edges)
   then (
-    let instruction_id = assert false in
+    let instruction_id = (Cfg_with_infos.cfg cfg_with_infos).instruction_id in
     Cfg_edge.Set.iter
       (fun { Cfg_edge.src; dst } ->
         let (_inserted_blocks : Cfg.basic_block list) =