RFR: 8346008: Fix recent NULL usage backsliding in Shenandoah

[William Kemper]

On Wed, 11 Dec 2024 16:10:06 GMT, Sonia Zaldana Calles <szaldana at openjdk.org> wrote:

> Hi all, 
> 
> This PR addresses [8346008](https://bugs.openjdk.org/browse/JDK-8346008). It's a follow-up from [8345647](https://bugs.openjdk.org/browse/JDK-8345647) with some cases I missed. 
> 
> Thanks, 
> Sonia

Thank you - looks good to me!

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Marked as reviewed by wkemper (Committer).

PR Review: https://git.openjdk.org/jdk/pull/22684#pullrequestreview-2496572142