RFR: 8341451: Remove C2HandleAnonOMOwnerStub

[Fei Yang]

On Thu, 3 Oct 2024 07:09:53 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

> [JDK-8319796](https://bugs.openjdk.org/browse/JDK-8319796) has been implemented on all platforms which had previous C2 implementations of LM_LIGHTWEIGHT that made use of C2HandleAnonOMOwnerStub.
> 
> The declaration is still left in the shared code, an a couple of platforms have the definitions still lingering. I propose we remove them.

Marked as reviewed by fyang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/21319#pullrequestreview-2344924640