RFR: 8370966: Create regression test for the hierarchical memory limit fix in JDK-8370572 [v2]

[Aleksey Shipilev]

On Mon, 10 Nov 2025 17:43:02 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> Please review this test-only enhancement. It creates a regression test for the Amazon ECS setup on cgroups v1 where the parent memory limit isn't visible inside the container and, thus, needs to rely on the cg v1 specific `hierarchical_memory_limit` token in `memory.stat`. The proposed test is cg v1 only and needs to be run as root. It's skipped otherwise. It's useful to have when working on refactorings like #27743  so as not to regress.
>> 
>> The other changes are an effort to reduce code duplication in the test code where similar patterns have been used in other container tests.
>> 
>> Testing (all on Linux x86_64):
>> - [x] CG version 2, run as root. Engine: docker. Test is skipped.
>> - [x] CG version 1, run as root. Engine: docker. Test passes and fails without the product fix of [JDK-8370572](https://bugs.openjdk.org/browse/JDK-8370572)
>> - [x] CG version 1, run as root. Engine: podman. Test passes and fails without the product fix of [JDK-8370572](https://bugs.openjdk.org/browse/JDK-8370572)
>> - [X] CG version 1, run as non-root. Test skipped.
>> - [x] GHA, though I don't think this is very useful for this change.
>> 
>> Thoughts?
>
> Severin Gehwolf has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Indenting and copyright

Still good.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28201#pullrequestreview-3444430112