Summary of the contribution

This adds --test-output= to run_end_to_end.sh, which is required for #9

Testing

Run run_end_to_end.sh, using different --test-output= or none, and observe the logs and outputs.

[x] Confirm that any associated issues are indicated in the pull request title
[x] Rebase your PR against the latest commit within the target branch
[x] Include steps to verify and test the intended change
[x] Write or update unit tests and/or integration tests to verify your changes
[x] Verify the basic functionality of the plugin by building and running locally via the end to end testing script
[x] Run shellcheck against any new or updated shell scripts, indicating the reasoning behind any disabled checks
[x] Indicate whether or not this is a breaking change
[x] Ensure that any new dependencies are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0