RFR: Improve handling of promotion and old generation evacuation failures

[Kelvin Nilsen]

On Wed, 6 Oct 2021 17:17:54 GMT, William Kemper <wkemper at openjdk.org> wrote:

> There are two changes here:
>  * A promotion failure will cause the old generation heuristic to request an old collection.
>  * An evacuation failure in the old generation will trigger a full collection.
> 
> Minor change:
>  * If an allocation failure has been detected, the control thread will not sleep at the bottom of its loop.

Thank you for these improvements.

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Marked as reviewed by kdnilsen (Committer).

PR: https://git.openjdk.java.net/shenandoah/pull/81