Add new Executor property to config test

[Gerg]

Thank you for submitting a pull request to the rep repository!

We appreciate the contribution. To help us understand the context for your pull request, please fill out this template to the best of your ability.

Please make sure to complete all of the following steps

1. Check the Contributing document on how to sign the CLA and run tests.
2. Submit your PR to this repo.
3. Submit an accompanying PR Review Request referencing this PR so the Diego Team knows to review your pull request.

• Note: this PR will not be reviewed unless you submit the PR Review Request.

---

Please provide the following information:

What is this change about?

Minor test update as part of cloudfoundry/diego-release#592.

What problem it is trying to solve?

See cloudfoundry/diego-release#592.

What is the impact if the change is not made?

The rep config test will not be up-to-date with executor config.

How should this change be described in diego-release release notes?

N/A

Please provide any contextual information.

Diego-release issue and associated PRs: cloudfoundry/diego-release#592
Root issue: cloudfoundry/routing-release#200