message: [cli] Don't use `tree-kill` for shutting down `startDevServer()` process in `vc dev`
  Follow-up to since using `tree-kill` here seems to make a CLI test hang forever.
diff: @@ -1040,7 +1040,12 @@ export default class DevServer {
  const { debug } = this.output;
  debug(`Killing builder dev server with PID ${pid}`);
  this.devServerPids.delete(pid);
  - await treeKill(pid);
  + try {
  + process.kill(pid, 'SIGTERM');
  + debug(`Killed builder dev server with PID ${pid}`);
  + } catch (err) {
  + debug(`Failed to kill builder dev server with PID ${pid}: ${err}`);
  + }
  }
  async send404(
  