Delete GitHub Actions workflow tests

[AndrewGable]

Problem

We added Github Action tests in #13604, and while most of the problems presented in the original issue are true, we are not getting a ton of value out of the tests at the moment. We write lots of little workflow bugs that are not caught by the tests and have to spend a lot of time keeping them working. This tradeoff does not seem worth it anymore.

Solution

• Delete the workflow_tests directory
• Delete the testGithubActionsWorkflows.yml file
• Delete the workflow-test script in package.json

[roryabraham]

PR merged. Thanks @AndrewGable