src: guard against nullptr deref in TimerWrapHandle::Stop

Refs: #34454

PR-URL: #34460
Reviewed-By: Jiawen Geng <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: David Carlier <[email protected]>

Author: addaleax

src/timer_wrap.cc

@@ -56,7 +56,8 @@ TimerWrapHandle::TimerWrapHandle(
 }
 
 void TimerWrapHandle::Stop() {
-  return timer_->Stop();
+  if (timer_ != nullptr)
+    return timer_->Stop();
 }
 
 void TimerWrapHandle::Close() {