RFR: 8330266: RISC-V: Restore frm to RoundingMode::rne after JNI

[Hamlin Li]

Hi,
Can you help to review this patch?
As discussed at: https://github.com/openjdk/jdk/pull/18758#pullrequestreview-1999982333, we'd better to do it.
Similar thing is done on aarch64, https://bugs.openjdk.org/browse/JDK-8320892

Thanks

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

Commit messages:
 - fix typo
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/18785/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18785&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8330266
  Stats: 25 lines in 5 files changed: 25 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18785.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18785/head:pull/18785

PR: https://git.openjdk.org/jdk/pull/18785