path: remove obsolete comment

Remove commented-out code that is leftover from a refactoring.

PR-URL: https://github.com/nodejs/node/pull/17023
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Lance Ball <lball@redhat.com>

lib/path.js

@@ -523,7 +523,6 @@ const win32 = {
     // This means that the user can use join to construct UNC paths from
     // a server name and a share name; for example:
     //   path.join('//server', 'share') -> '\\\\server\\share\\')
-    //var firstPart = paths[0];
     var needsReplace = true;
     var slashCount = 0;
     var code = firstPart.charCodeAt(0);