RFR: 8340657: [PPC64] SA determines wrong unextendedSP

[Yasumasa Suenaga]

On Mon, 23 Sep 2024 15:15:27 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> Using the FP as raw_unextendedSP is wrong and causes problems like [JDK-8339772](https://bugs.openjdk.org/browse/JDK-8339772).
> "test/hotspot/jtreg/serviceability" tests have passed with this PR.

I'm not familiar with call frames on PPC64 TBH, but it looks good and all of SA tests evidences the fix is correct. So I agree with this change.

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Marked as reviewed by ysuenaga (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21139#pullrequestreview-2324409388