Fix wasmfs.test_fs_nodefs_readdir on Windows. (#25039)

Windows does not support fifos, so the test expectation needs to look
different.

Author: juj

test/fs/test_nodefs_readdir.wasmfs_win.out

@@ -0,0 +1,13 @@
+listing contents of dir=/
+.
+..
+dev
+tmp
+listing contents of dir=/working
+.
+..
+existing
+stdout
+test_nodefs_readdir.js
+test_nodefs_readdir.wasm
+success

test/test_core.py

@@ -5885,8 +5885,9 @@ def test_fs_nodefs_readdir(self):
     os.makedirs('existing/a')
     self.cflags += ['-lnodefs.js']
     suffix = ''
+    # Windows does not add a name_pipe to test expectations.
     if self.get_setting('WASMFS'):
-      suffix = '.wasmfs'
+      suffix = '.wasmfs_win' if WINDOWS else '.wasmfs'
     elif self.is_wasm2js():
       suffix = ".wasm2js"
     self.do_run_in_out_file_test('fs/test_nodefs_readdir.c', out_suffix=suffix)