timers: stop all timers on teardown

src/nvim/eval.c

@@ -16609,6 +16609,14 @@ static void timer_free_cb(TimeWatcher *tw, void *data)
   xfree(timer);
 }
 
+void timer_teardown(void)
+{
+  timer_T *timer;
+  map_foreach_value(timers, timer, {
+    timer_stop(timer);
+  })
+}
+
 /*
  * "tolower(string)" function
  */

src/nvim/main.c

@@ -161,6 +161,7 @@ void event_teardown(void)
   input_stop();
   channel_teardown();
   process_teardown(&main_loop);
+  timer_teardown();
   server_teardown();
   signal_teardown();
   terminal_teardown();