Skip -Xfuture test for Java 24+

[gjwatts]

• I have considered the risk of behavior change or other zero migration impact (https://github.com/OpenLiberty/open-liberty/wiki/Behavior-Changes).
• If this PR fixes an Issue, the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN" (verify release bug label if applicable: https://github.com/OpenLiberty/open-liberty/wiki/Open-Liberty-Conventions).
• If this PR resolves an external Known Issue (including APARS), the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN".

Fixes #30451

Limits the test that uses the -Xfuture argument to only run on Java 23 or earlier.

[gjwatts]

FYI, I intentionally did not update the copyright date since there was no real code change involved in this PR.

[gjwatts]

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[hlhoots]

LGTM