Interrupt orphan processing after every transaction

This makes orphan processing work like handling getdata messages:
After every actual transaction validation attempt, interrupt
processing to deal with messages arriving from other peers.

src/net.h

@@ -739,6 +739,8 @@ public:
     CAmount lastSentFeeFilter{0};
     int64_t nextSendTimeFeeFilter{0};
 
+    std::set<uint256> orphan_work_set;
+
     CNode(NodeId id, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn, SOCKET hSocketIn, const CAddress &addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const CAddress &addrBindIn, const std::string &addrNameIn = "", bool fInboundIn = false);
     ~CNode();
     CNode(const CNode&) = delete;