RFR: 8293566: RISC-V: Clean up push and pop registers [v5]

[Aleksey Shipilev]

On Mon, 12 Sep 2022 02:34:56 GMT, Feilong Jiang <fjiang at openjdk.org> wrote:

>> Currently, riscv port has two implementations of `push_reg` and `pop_reg`.
>> The bitset version can be replaced with the RegSet version for better readability.
>> 
>> For example, if we want to push x10 and x11, pushing register with bitset would be like:
>> 
>> push_reg(0xc00, sp)
>> 
>> 
>> while pushing register with RegSet will be more clear:
>> 
>> push_reg(RegSet::of(x10, x11), sp);
>> 
>> 
>> Testing:
>> 
>> - hotspot and jdk ter1 on QEMU without new failures
>
> Feilong Jiang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix

Looks good to me.

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Marked as reviewed by shade (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10227