[CPP][Analyzers] turn on warning 4189 (#21522)

* Turn on 4189 and fix code

* changes from PR comments

src/runner/main.cpp

@@ -460,7 +460,6 @@ int WINAPI WinMain(HINSTANCE /*hInstance*/, HINSTANCE /*hPrevInstance*/, LPSTR l
 
         // Apply the general settings but don't save it as the modules() variable has not been loaded yet
         apply_general_settings(general_settings, false);
-        int rvalue = 0;
         const bool elevated = is_process_elevated();
         const bool with_dont_elevate_arg = cmdLine.find("--dont-elevate") != std::string::npos;
         const bool run_elevated_setting = general_settings.GetNamedBoolean(L"run_elevated", false);