[Core] Make third party library thread count static in worker #55215
Description
What happened + What you expected to happen
This is related to PR #54988
Today, the thread count per worker is not static, and can vary due to some third party libraries like jemalloc and grpc. We should come up with a way to make the thread count more predictable (and lower when at all possible). When we fix this, we should resolve the TODO in the test in the above PR and simplify the logic (without making the test flaky).
Versions / Dependencies
Linux, all versions of ray
Reproduction script
Run the test_worker_thread_count test in the PR after changing the assert to not include the 'or' clause.
Issue Severity
Low: It annoys or frustrates me.