RFR: 8367048: RISC-V: Correct pipeline descriptions of the architecture [v2]

[Fei Yang]

On Tue, 9 Sep 2025 00:24:38 GMT, Dingli Zhang <dzhang at openjdk.org> wrote:

>> Hi,
>> Can you help to review this patch? Thanks!
>> 
>> This patch updates the RISC-V pipeline attributes to variable_size_instructions to properly account for the 2-byte compressed instructions from the C extension. 
>> Furthermore, it increases the max_instructions_per_bundle to 4 and adjusts the instruction_unit_size to match 4-issue RISC-V hardware like the UR-CP100.
>> 
>> ### Test
>> - [x] Run tier1 and tier2 on sg2042
>
> Dingli Zhang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix typo

Marked as reviewed by fyang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27134#pullrequestreview-3198583207