[wallet] Keep track of the best block time in the wallet

Move nTimeBestReceived (which is only used for wallet
rebroadcasts) into the wallet.

src/net_processing.cpp

@@ -175,8 +175,6 @@ namespace {
     /** Expiration-time ordered list of (expire time, relay map entry) pairs. */
     std::deque<std::pair<int64_t, MapRelay::iterator>> vRelayExpiration GUARDED_BY(cs_main);
 
-    std::atomic<int64_t> nTimeBestReceived(0); // Used only to inform the wallet of when we last received a block
-
     struct IteratorComparator
     {
         template<typename I>
@@ -1121,8 +1119,6 @@ void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CB
         });
         connman->WakeMessageHandler();
     }
-
-    nTimeBestReceived = GetTime();
 }
 
 /**
@@ -3555,7 +3551,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto)
         // transactions become unconfirmed and spams other nodes.
         if (!fReindex && !fImporting && !IsInitialBlockDownload())
         {
-            GetMainSignals().Broadcast(nTimeBestReceived, connman);
+            GetMainSignals().Broadcast(connman);
         }
 
         //