Cygwin: pty: Add missing DeleteProcThreadAttributeList() call

Currently, the cleanup path of setup_pseudoconsole() is missing
DeleteProcThreadAttributeList() call, while microsoft's document
requires that and the normal path has it.
https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-initializeprocthreadattributelist

This patch adds DeleteProcThreadAttributeList() call to the cleanup
path.

Fixes: bb42852 ("Cygwin: pty: Implement new pseudo console support.")
Suggested-by: Johannes Schindelin <[email protected]>
Signed-off-by: Takashi Yano <[email protected]>
Reviewed-by: Corinna Vinschen <[email protected]>
(cherry picked from commit 11a835f)

Author: tyan0

winsup/cygwin/fhandler/pty.cc

@@ -3530,7 +3530,7 @@ fhandler_pty_slave::setup_pseudoconsole ()
 				      PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE,
 				      hpcon, sizeof (hpcon), NULL, NULL))
 
-	goto cleanup_heap;
+	goto cleanup_proc_thread_attr;
 
       hello = CreateEvent (&sec_none, true, false, NULL);
       goodbye = CreateEvent (&sec_none, true, false, NULL);
@@ -3699,6 +3699,8 @@ fhandler_pty_slave::setup_pseudoconsole ()
   CloseHandle (goodbye);
   CloseHandle (hr);
   CloseHandle (hw);
+cleanup_proc_thread_attr:
+  DeleteProcThreadAttributeList (si.lpAttributeList);
 cleanup_heap:
   HeapFree (GetProcessHeap (), 0, si.lpAttributeList);
 cleanup_pseudo_console: