EXPERIMENT: run serve-listing on Windows too (test if readdir_n hangs)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: hhugo

test/dune

@@ -27,20 +27,8 @@
 ; cleanup. They run on every platform, including Windows.
 
 (cram
- (applies_to serve serve-cli)
+ (applies_to serve serve-listing serve-cli)
  (package ocsigenserver)
  (deps
   server-test-helpers.sh
   (package ocsigenserver)))
-
-; The directory listing relies on Lwt_unix.readdir_n, which hangs on Windows
-; (see the windows-serve-support branch for a fix), so it runs off Windows.
-
-(cram
- (applies_to serve-listing)
- (package ocsigenserver)
- (enabled_if
-  (<> %{os_type} Win32))
- (deps
-  server-test-helpers.sh
-  (package ocsigenserver)))