add new event for subxact

Signed-off-by: jc_zhang <zhangjingchang1@huawei.com>

src/include/access/xact.h

@@ -62,6 +62,7 @@ typedef void (*XactCallback)(XactEvent event, void* arg);
 typedef enum {
     SUBXACT_EVENT_START_SUB,
     SUBXACT_EVENT_COMMIT_SUB,
+    SUBXACT_EVENT_CLEANUP_SUB,
     SUBXACT_EVENT_ABORT_SUB
 } SubXactEvent;