RFR: 8340186: Shenandoah: Missing load_reference_barrier_phantom_narrow match in is_shenandoah_lrb_call

[Vladimir Kozlov]

On Mon, 16 Sep 2024 10:38:12 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> [JDK-8256999](https://bugs.openjdk.org/browse/JDK-8256999) added `ShenandoahRuntime::load_reference_barrier_phantom_narrow`, but missed adding it to `ShenandoahBarrierSetC2::is_shenandoah_lrb_call`. It is currently innocuous, as there are no users of `is_shenandoah_lrb_call`, but it will be important when [JDK-8340183](https://bugs.openjdk.org/browse/JDK-8340183) lands.

Trivial ;)

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Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21016#pullrequestreview-2307108763