[riscv-port-jdk17u:riscv-port] RFR: 8292867: RISC-V: Simplify weak CAS return value handling

[Fei Yang]

On Sat, 15 Apr 2023 16:26:27 GMT, Dingli Zhang <dzhang at openjdk.org> wrote:

> Please review this backport to riscv-port-jdk17u.
> Backport of [JDK-8292867](https://bugs.openjdk.org/browse/JDK-8292867). Applies cleanly.
> 
> Testing:
> 
> - Tier1-3 passed without new failure on unmacthed (release).

Marked as reviewed by fyang (Lead).

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PR Review: https://git.openjdk.org/riscv-port-jdk17u/pull/43#pullrequestreview-1387149667