[jdk23u] RFR: 8345296: AArch64: VM crashes with SIGILL when prctl is disallowed

[Kerem Kat]

Ref. https://github.com/openjdk/jdk/pull/22479

> We have caught this in some prod environments, where prctl is forbidden by the sandboxing mechanism. This fails the JVM

Does not apply cleanly, the backport depends on `FloatRegister` changes from [JDK-8339063](https://bugs.openjdk.org/browse/) which are included in `src/hotspot/cpu/aarch64/register_aarch64.hpp`.

Additional testing:

- [x] Verified the bug is fixed with the seccomp repro from [JDK-8345296](https://bugs.openjdk.org/browse/JDK-8345296?focusedId=14727386&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14727386): Segfault without the patch, works with.

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Commit messages:
 - Backport 3c60f0b2bb75150d49da9ab94d88b767275de5e2

Changes: https://git.openjdk.org/jdk23u/pull/231/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk23u&pr=231&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345296
  Stats: 22 lines in 2 files changed: 19 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk23u/pull/231.diff
  Fetch: git fetch https://git.openjdk.org/jdk23u.git pull/231/head:pull/231

PR: https://git.openjdk.org/jdk23u/pull/231