[cleanup] remove engine-use-ray

[simon-mo]

Finally removing this. We should start looking at worker-use-ray too.

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.
Just a reminder: PRs would not trigger full CI run by default. Instead, it would only run fastcheck CI which consists a small and essential subset of CI tests to quickly catch errors. You can run other CI tests on top of default ones by unblocking the steps in your fast-check build on Buildkite UI.

Once the PR is approved and ready to go, please make sure to run full CI as it is required to merge (or just use auto-merge).

To run full CI, you can do one of these:

• Comment /ready on the PR
• Add ready label to the PR
• Enable auto-merge.

🚀

[youkaichao]

glad that this can be removed, we don't see any users complaining at #7045 .

please check the failed tests and see if they are relevant.

[njhill]

Thanks @simon-mo! It would be great to get this merged asap since it simplifies other changes being made (and the code in general).

I think at some point at least, some of the tests "relied" on this setting to avoid the issues with re-initializing a vllm in the same process, especially in multi-worker cases. There have been some improvements to that but it might be that something else is needed instead to get around this, like splitting into separate tests / pytest invocations for example.

[simon-mo]

superseded by #8126