egg在stop之后会有一个node进程一直存在

### Your detail info about the Bug:

当通过start启动一个egg服务，stop之后会留下一个node进程。

### Reproduction Repo

https://github.com/no_rep

### Node Version

14.18.3

### Eggjs Version

3

### Plugin Name and its version

"egg-cors": "^2.2.3", "egg-scripts": "^2", "egg-sequelize": "^6.0.0",

### Platform and its version

centos 7.3