init: add exe name to bitcoind, bitcoin-node -version output to be able to distinguish these in tests

Github-Pull: #33229
Rebased-From: 0972f55040

src/init/bitcoind.cpp

@@ -18,6 +18,8 @@ using node::NodeContext;
 
 namespace init {
 namespace {
+const char* EXE_NAME = "bitcoind";
+
 class BitcoindInit : public interfaces::Init
 {
 public:
@@ -34,6 +36,7 @@ public:
         return MakeWalletLoader(chain, *Assert(m_node.args));
     }
     std::unique_ptr<interfaces::Echo> makeEcho() override { return interfaces::MakeEcho(); }
+    const char* exeName() override { return EXE_NAME; }
     NodeContext& m_node;
 };
 } // namespace