🐛 Bug Report

Using jest-dev-server, set a command like:

module.exports = {
  command: 'npm run start',
  launchTimeout: 1000,
}

If the timeout occurs, you get this message:

Server has taken more than 1000ms to start.

The problem here is that jest-dev-server then never sends the proper signals to the processes started by the command, meaning they get hanging. As a comparison, pressing ´ctrl+c` after the server has started properly cleans up the resources.

To Reproduce

Add the above config and a very short launchTimeout and notice how the started command never stops (check e.g. via the ps command).

Expected behavior

jest-dev-server should send the proper signals to launched command, even after a launchTimeout occured.