(buildkite 6/n) Get coverage working again

Summary:
Coverage reporting has been broken / not running for ~2 months. This diff fixes it and gets coverage working again.

• Rename coverage-image to buildkite-coverage for consistency.
• Disable coverage on tests where coverage is not working correctly
• Disable broken lcov for js_modules (we weren't using it anyway) - we should fix this at some point FYI @dish

Depends on D5775

Test Plan: buildkite

Reviewers: alangenfeld, dgibson, max

Reviewed By: dgibson

Subscribers: dish

Differential Revision: https://dagster.phacility.com/D5776