refactor: Remove unused code

src/chainparams.cpp

@@ -559,9 +559,3 @@ void SelectParams(const std::string& network)
     SelectBaseParams(network);
     globalChainParams = CreateChainParams(gArgs, network);
 }
-
-std::ostream& operator<<(std::ostream& o, const AssumeutxoData& aud)
-{
-    o << strprintf("AssumeutxoData(%s, %s)", aud.hash_serialized.ToString(), aud.nChainTx);
-    return o;
-}