[jdk23u] RFR: 8339248: RISC-V: Remove li64 macro assembler routine and related code

[Gui Cao]

Hi, The same issue also exists in jdk23u. So I would like to backport [JDK-8339248](https://bugs.openjdk.org/browse/JDK-8339248) to jdk23u. with this patch ,it will save us some unnecessary runtime checks. This is a risc-v specific change. Backport is clean, risk is low.

### Testing
- [x] Run hotspot:tier1 tests on SOPHON SG2042 (fastdebug)

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

Commit messages:
 - Backport 392bdd5734e0ad4e616d52bb7bcafcf85dccbf34

Changes: https://git.openjdk.org/jdk23u/pull/90/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk23u&pr=90&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339248
  Stats: 111 lines in 2 files changed: 0 ins; 111 del; 0 mod
  Patch: https://git.openjdk.org/jdk23u/pull/90.diff
  Fetch: git fetch https://git.openjdk.org/jdk23u.git pull/90/head:pull/90

PR: https://git.openjdk.org/jdk23u/pull/90