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.
------------- Commit messages: - 8340657: [PPC64] SA determines wrong unextendedSP Changes: https://git.openjdk.org/jdk/pull/21139/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21139&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8340657 Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/21139.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21139/head:pull/21139 PR: https://git.openjdk.org/jdk/pull/21139
