sd-event: drop inotify event from buffer when no event source is triggered

Even when we receive an inotify event, there is no relevant event source
exists. In that case, we need to drop the event from the buffer,
otherwise we cannot escape from the loop.

Fixes #38265.

src/libsystemd/sd-event/sd-event.c

@@ -3955,9 +3955,12 @@ static int event_inotify_data_process(sd_event *e, InotifyData *d) {
                         }
                 }
 
-                /* Something pending now? If so, let's finish, otherwise let's read more. */
+                /* Something pending now? If so, let's finish. */
                 if (d->n_pending > 0)
                         return 1;
+
+                /* otherwise, drop the event and let's read more */
+                event_inotify_data_drop(e, d, sz);
         }
 
         return 0;