[jdk17u-dev] RFR: 8310656: RISC-V: __builtin___clear_cache can fail silently.

[Ludovic Henry]

Hi all,

This pull request contains a backport of commit [5f1d762750a0d4c20da5b23d54f922dbb5cbbe34](https://github.com/openjdk/jdk21u/commit/5f1d762750a0d4c20da5b23d54f922dbb5cbbe34) from the [openjdk/jdk21u](https://git.openjdk.org/jdk21u) repository.

The commit being backported was authored by Robbin Ehn on 2 Jul 2023 and was reviewed by Ludovic Henry, Thomas Stuefe and Fei Yang.

Thanks!

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Commit messages:
 - 8310656: RISC-V: __builtin___clear_cache can fail silently.

Changes: https://git.openjdk.org/jdk17u-dev/pull/1968/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1968&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310656
  Stats: 131 lines in 3 files changed: 126 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1968.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1968/head:pull/1968

PR: https://git.openjdk.org/jdk17u-dev/pull/1968