RFR: 8340181: Shenandoah: Cleanup ShenandoahRuntime stubs

[William Kemper]

On Tue, 24 Sep 2024 08:52:21 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Noticed this while working on Leyden, which has to enumerate Shenandoah stubs for code archival to work.
> 
> `ShenandoahRuntime::shenandoah_clone_barrier` is excessive name. `ShenandoahRuntime::arraycopy_barrier_oop_entry` and friends is not covered by `JRT_LEAF`. This change hopefully homogenizes the namings for the stubs.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `hotspot_gc_shenandoah` 
>  - [x] Linux AArch64 server fastdebug, `hotspot_gc_shenandoah`

Marked as reviewed by wkemper (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/21152#pullrequestreview-2334085291