Fix an invalid check in Windows implementation of directory_iterator factory function

[sl]

Summary

Do actually check the last symbol of given file path.

lib/Support/Windows/Path.inc

 
   // Convert path to the format that Windows is happy with.
   if (path_utf16.size() > 0 &&
-      !is_separator(path_utf16[path.size() - 1]) &&
-      path_utf16[path.size() - 1] != L':') {
+      !is_separator(path_utf16[path_utf16.size() - 1]) &&
+      path_utf16[path_utf16.size() - 1] != L':') {
     path_utf16.push_back(L'\\');
     path_utf16.push_back(L'*');
   } else {