Runner tests: fix async functions with no await

What does this MR do and why?

Fix async functions with no await in all jest runner tests.

See #397674 (closed)

Screenshots or screen recordings

NA

How to set up and validate locally

You may run this command to verify:

$ yarn eslint --rule 'require-await: error' spec/frontend/ci/runner/

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #397674 (closed)