[jdk21u-dev] 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

Backport depends on [JDK-8339063](https://bugs.openjdk.org/browse/) which is included.

JDK-8339063 did not apply cleanly, resolved conflict in `src/hotspot/cpu/aarch64/aarch64.ad` by keeping const qualifiers. These were removed in [JDK-8310948](https://bugs.openjdk.org/browse/JDK-8310948) which doesn't apply cleanly either.

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
 - 8339063: [aarch64] Skip verify_sve_vector_length after native calls if SVE supports 128 bits VL only

Changes: https://git.openjdk.org/jdk21u-dev/pull/1222/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1222&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345296
  Stats: 73 lines in 7 files changed: 45 ins; 14 del; 14 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1222.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1222/head:pull/1222

PR: https://git.openjdk.org/jdk21u-dev/pull/1222