[jdk25] RFR: 8360405: [PPC64] some environments don't support mfdscr instruction

[Martin Doerr]

Clean backport of [JDK-8360405](https://bugs.openjdk.org/browse/JDK-8360405).

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Commit messages:
 - Backport f71d64fbeb0c196fd825241ff86d3a103d05a842

Changes: https://git.openjdk.org/jdk/pull/25972/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25972&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360405
  Stats: 73 lines in 4 files changed: 33 ins; 0 del; 40 mod
  Patch: https://git.openjdk.org/jdk/pull/25972.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25972/head:pull/25972

PR: https://git.openjdk.org/jdk/pull/25972