RFR: 8344265: RISC-V: Remove unused function get_previous_sp_entry [v2]

[Gui Cao]

> Hi, I noticed that there are a several unused functions here that are currently only used in the x86 architecture, not used in RISC-V.
> 
> ### Testing
>  - [x] release & fastdebug cross-build  linux-riscv64 OK
>  - [x] release & fastdebug build  on SOPHON SG2042
> - [ ] Run tier1 tests on SOPHON SG2042 (release)

Gui Cao has updated the pull request incrementally with one additional commit since the last revision:

  Remove large_byte_array_inflate function

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22130/files
  - new: https://git.openjdk.org/jdk/pull/22130/files/446c8c28..f44aabd4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22130&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22130&range=00-01

  Stats: 6 lines in 2 files changed: 0 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22130.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22130/head:pull/22130

PR: https://git.openjdk.org/jdk/pull/22130