Run separate CLI server for test discovery

[koesie10]

This is a workaround for the fact that the resolveTests command can take a long time to run for large workspaces. We don't want to block other CLI commands from running while this is happening, so we'll create a separate CLI server just for this.

I haven't yet tested how this behaves when the CLI is being updated, but I first wanted to validate that this is something we want to do.

Checklist

• [ ] CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• [ ] Issues have been created for any UI or other user-facing changes made by this pull request.
• [ ] [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.