[riscv-port-jdk11u:riscv-port] RFR: 8291893: riscv: remove fence.i used in user space [v3]

[Ludovic Henry]

On Thu, 28 Mar 2024 02:16:19 GMT, Gui Cao <gcao at openjdk.org> wrote:

>> Please help review this backport to riscv-port-jdk11u.
>> Backport of [JDK-8291893](https://bugs.openjdk.org/browse/JDK-8291893)
>> 
>> In addition to the backport [8291947](https://bugs.openjdk.org/browse/JDK-8291947), [8310656](https://bugs.openjdk.org/browse/JDK-8310656) to align and minimize the difference with 17u upstream.
>> 
>> Testing:
>> 
>> - [x] Run tier1-3 tests on SOPHON SG2042 (release)
>
> Gui Cao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add extra include header

Marked as reviewed by luhenry (no project role).

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PR Review: https://git.openjdk.org/riscv-port-jdk11u/pull/16#pullrequestreview-1965686850