RFR: 8294729: [s390] Implement nmethod entry barriers

[Lutz Schmidt]

On Tue, 4 Oct 2022 14:27:09 GMT, Tyler Steele <tsteele at openjdk.org> wrote:

> This draft PR implements native method barriers on s390. When complete, this will fix the build, and bring the other benefits of [JDK-8290025](https://bugs.openjdk.org/browse/JDK-8290025) to that platform.

LGTM as well, finally!
Congratulations and thank you for your patience and perseverance.

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Marked as reviewed by lucy (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10558