[ci] set timeout for test_oot_registration.py

[youkaichao]

observed multiple errors in the main branch ci, e.g. https://buildkite.com/vllm/ci-aws/builds/6093#019113ce-d6dd-4cb5-8dda-d5d66dd344e9 and https://buildkite.com/vllm/ci-aws/builds/6084#019111f1-a753-42f7-9b32-2fb916f22866 .

They error with:

AssertionError: Error in memory profiling. This happens when the GPU memory was not properly cleaned up before initializing the vLLM instance.

It turns out to be flaky. One retry works https://buildkite.com/vllm/ci-aws/builds/6084#019113eb-bc79-48e8-8849-57f729e30475 , while another does not.

Still investigating, but we need to add timeout to the test, to avoid hanging for one hour.

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.
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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:

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