Unstable test `random_drop_message`

link: https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Fticdc%2Fpull_cdc_mysql_integration_heavy/detail/pull_cdc_mysql_integration_heavy/4383/pipeline/388/

1. maintainer ask dispatcher 246851790476395481311654354300970078885 move from cdc1-restart-1.log to other nodes.
2. cdc1-restart-1.log remove dispatcher 246851790476395481311654354300970078885
3. While maintainer don't receive the remove finish infomration from cdc1-restart-1.log, although maintainer repeated to send message to remove dispatcher 246851790476395481311654354300970078885 to cdc1-restart-1.log
4. So the move operator can't finish, and the dispatcher can't continue to sync data.

While it's quite strange why maintainer can't receive the message about 246851790476395481311654354300970078885 status.

One possible reason is that these messages were dropped by the failpoint, but this is very unlikely.
Since this issue hasn't been reproduced, I'm putting it on hold for now.