[riscv64] Add s10 into allocate reg

  3103425 had delete s10 from scratch reg

Bug: v8:12124
Change-Id: I23b34c7ce28f129137683204f12a19a46325f91a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3156291


Reviewed-by: Ji Qiu <qiuji@iscas.ac.cn>
Commit-Queue: Ji Qiu <qiuji@iscas.ac.cn>
Auto-Submit: Yahan Lu <yahan@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#76861}