RFR: 8327383: Clean up _Stalled and _Spinner fields

[Coleen Phillimore]

On Thu, 14 Mar 2024 15:03:41 GMT, Fredrik Bredberg <fbredberg at openjdk.org> wrote:

> Removed the `_Stalled` and the `_Spinner` fields from the object synchronization code, since they are not used anymore.
> 
> Passes tier1-5

Thanks for cleaning these up.

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Marked as reviewed by coleenp (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18306#pullrequestreview-1938826143