run-e2e.mjs and run-bidi-server.mjs should kill child process on exit

[OrKoN]

the code to achieve this can be found in https://github.com/puppeteer/puppeteer and, for example, on Linux it involves calling the kill with the group id:

          // on linux the process group can be killed with the group id prefixed with
          // a minus sign. The process group id is the group leader's pid.
          const processGroupId = -this.#browserProcess.pid;
          process.kill(processGroupId, 'SIGKILL');

as the fallback the node child_process kill API can be used.

Currently, you can reproduce the issue by running chromedriver e2e and checking the matchLine to always error. This results in a dangling chromedriver process that can only be killed manually.

cc @Lightning00Blade @sadym-chromium

[OrKoN]

I think in general it might be OS-specific but I do not think Node will try to auto-kill child processes.