Fix handle leak: always close thread handle in remove(), not only when queue removal succeeds

Agent-Logs-Url: https://github.com/acl-dev/open-coroutine/sessions/2348f69b-81c0-4cf0-9c52-9079bf4b243c

Co-authored-by: loongs-zhang <38336731+loongs-zhang@users.noreply.github.com>

Author: Copilot

core/src/monitor.rs

@@ -529,7 +529,7 @@ impl Monitor {
         let queue = unsafe { &mut *instance.notify_queue.get() };
         let removed = queue.remove(node);
         #[cfg(windows)]
-        if removed && node.thread_handle != 0 {
+        if node.thread_handle != 0 {
             unsafe {
                 let _ = CloseHandle(node.thread_handle as HANDLE);
             }