fix(sync): fix AddressSanitizer error

source/libs/sync/src/syncMain.c

@@ -1040,6 +1040,7 @@ void syncNodeClose(SSyncNode* pSyncNode) {
 
   ret = raftStoreClose(pSyncNode->pRaftStore);
   ASSERT(ret == 0);
+  pSyncNode->pRaftStore = NULL;
 
   syncRespMgrDestroy(pSyncNode->pSyncRespMgr);
   pSyncNode->pSyncRespMgr = NULL;
@@ -2174,10 +2175,18 @@ static void syncNodeEqPeerHeartbeatTimer(void* param, void* tmrId) {
   SSyncNode*        pSyncNode = pData->pSyncNode;
   SSyncTimer*       pSyncTimer = pData->pTimer;
 
+  if (pSyncNode == NULL) {
+    return;
+  }
+
   if (pSyncNode->state != TAOS_SYNC_STATE_LEADER) {
     return;
   }
 
+  if (pSyncNode->pRaftStore == NULL) {
+    return;
+  }
+
   // sNTrace(pSyncNode, "eq peer hb timer");
 
   int64_t timerLogicClock = atomic_load_64(&pSyncTimer->logicClock);