Get rid of TestNet()

src/chainparams.h

@@ -120,9 +120,4 @@ void SelectParams(CChainParams::Network network);
  */
 bool SelectParamsFromCommandLine();
 
-inline bool TestNet() {
-    // Note: it's deliberate that this returns "false" for regression test mode.
-    return Params().NetworkID() == CChainParams::TESTNET;
-}
-
 #endif