net: add nLastBlockTime/TXTime to CNodeStats, CNode::copyStats

src/net.h

@@ -619,6 +619,8 @@ public:
     bool fRelayTxes;
     int64_t nLastSend;
     int64_t nLastRecv;
+    int64_t nLastTXTime;
+    int64_t nLastBlockTime;
     int64_t nTimeConnected;
     int64_t nTimeOffset;
     std::string addrName;