RFR: 7903671: jcstress: Update buffer tests for JDK-8318966

[Aleksey Shipilev]

On Wed, 26 Feb 2025 17:50:28 GMT, Jiří Vaněk <jvanek at openjdk.org> wrote:

> part 1:  Detecting jdk of target VM and exuding illegible tests
> 
> This is prequel to full fixing of CODETOOLS-7903671. This PR detects target JDK version and then disables illegible tests.
> part 2 will be done in templates of affected tests and logic around generating the classes from them. In meantime this should server.
> 
> The jdk detection will be most likely used anyway. WDYT? If we agree on similar approach, I will create a new bug for this PR only.

To emphasize, my point is that `alignment(8)` is a behavior that _someone_ likely depends on in earlier JDKs. We need to continue testing that. So `alignment(8)` should stay until the last JDK that supports it, dies.  Yes, it would make sense to make sure that `alignment(8)` return `API mismatch` when run with incompatible JDK. I thought it does. If it does not, that would definitely need improvement.

-------------

PR Comment: https://git.openjdk.org/jcstress/pull/159#issuecomment-2949632717