simplify streaming interfaces by task-local epoch values

[BugenZhao]

After #9488, we're now able to retrieve the current epoch directly with a static function epoch() from the task-local storage, as long as we're under the streaming execution. In this way, some interfaces can be simplified since there's no need to pass an epoch value or maintain the epoch value inside of the structure anymore.

• State Table
• LRU Cache

[github-actions]

This issue has been open for 60 days with no activity. Could you please update the status? Feel free to continue discussion or close as not planned.

[github-actions]

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