RFR: 8353829: RISC-V: Auto-enable several more extensions for debug builds

[Fei Yang]

Hi,
Please consider this followup change after https://bugs.openjdk.org/browse/JDK-8353344.
This adds detection and enablement of two more extensions: Ztso and Zacas.
Testing: hs:tier1-hs:tier3 tested with qemu-system equipmented with these extensions.

-------------

Commit messages:
 - 8353829: RISC-V: Auto-enable several more extensions for debug builds

Changes: https://git.openjdk.org/jdk/pull/24478/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24478&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353829
  Stats: 10 lines in 1 file changed: 10 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24478.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24478/head:pull/24478

PR: https://git.openjdk.org/jdk/pull/24478