[riscv-port-jdk11u:riscv-port] RFR: 8339248: RISC-V: Remove li64 macro assembler routine and related code

[Fei Yang]

On Tue, 3 Sep 2024 12:36:16 GMT, Gui Cao <gcao at openjdk.org> wrote:

> Hi, The same issue also exists in riscv-port-jdk11u. So I would like to backport [JDK-8339248](https://bugs.openjdk.org/browse/JDK-8339248) to riscv-port-jdk11u. with this patch ,it will save us some unnecessary runtime checks. This is a risc-v specific change, risk is low.
> 
> ### Testing
> - [x] Run hotspot:tier1 tests on SOPHON SG2042 (release)

Looks good. Thanks.

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Marked as reviewed by fyang (Lead).

PR Review: https://git.openjdk.org/riscv-port-jdk11u/pull/27#pullrequestreview-2277332570