path: fix win32 parse regression

This fixes the parse function for single character input that are not
a path separator.

PR-URL: https://github.com/nodejs/node/pull/26912
Fixes: https://github.com/nodejs/node/issues/26911
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/path.js

@@ -830,6 +830,7 @@ const win32 = {
         ret.root = ret.dir = path;
         return ret;
       }
+      ret.base = ret.name = path;
       return ret;
     }
     // Try to match a root

test/parallel/test-path-parse-format.js

@@ -51,6 +51,7 @@ const winPaths = [
 ];
 
 const winSpecialCaseParseTests = [
+  ['t', { base: 't', name: 't', root: '', dir: '', ext: '' }],
   ['/foo/bar', { root: '/', dir: '/foo', base: 'bar', ext: '', name: 'bar' }],
 ];