Remove no longer necessary WinCmdLineArgs class

This change removes one use case of `std::wstring_convert`, which is
deprecated in C++17 and removed in C++26. Other uses remain for now.

src/bitcoind.cpp

@@ -259,11 +259,6 @@ static bool AppInit(NodeContext& node)
 
 MAIN_FUNCTION
 {
-#ifdef WIN32
-    common::WinCmdLineArgs winArgs;
-    std::tie(argc, argv) = winArgs.get();
-#endif
-
     NodeContext node;
     int exit_status;
     std::unique_ptr<interfaces::Init> init = interfaces::MakeNodeInit(node, argc, argv, exit_status);