[deflakey] Deflakey test_redis_tls

[fishbone]

Why are these changes needed?

The test sometimes got timeout is because the key generation takes a long time. This fix just pre-generate the related files and use that to save time.

Related issue number

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• Testing Strategy
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  • This PR is not tested :(

[fishbone]

Seems not working https://buildkite.com/ray-project/premerge/builds/8714#018b3a56-f38a-4e37-8b3c-db83085a3254

[fishbone]

25143:M 16 Oct 2023 21:50:19.847 # Failed to load certificate: /root/.cache/bazel/_bazel_root/1df605deb6d24fc8068f6e25793ec703/execroot/com_github_ray_project_ray/bazel-out/k8-opt/bin/python/ray/tests/test_redis_tls.runfiles/com_github_ray_project_ray/python/ray/tests/tls/redis.crt: error:02001002:system library:fopen:No such file or directory
 

<br class="Apple-interchange-newline">

Different error. Seems path is not setup correctly.