RFR: 8278551: Shenandoah: Adopt WorkerThread::worker_id() to replace Shenandoah specific implementation [v3]

[Roman Kennke]

On Wed, 15 Dec 2021 19:33:32 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

>> Shenandoah stores worker_id in ThreadLocalData for the same purpose as JDK-8278351.
>> 
>> After JDK-8278351, Shenandoah should adopt WorkerThread::worker_id() from JDK-8278351 to replace its own implementation.
>> 
>> Test:
>> - [x] hotspot_gc_shenandoah
>
> Zhengyu Gu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove bad assertion

Makes sense and looks good! Thank you!

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Marked as reviewed by rkennke (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6853