Adapt to change in JavaCore's new API about supported Java versions

[HannesWell]

The new API is enhanced in https://github.com/eclipse-jdt/eclipse.jdt.core/pull/2770

Author checklist

• [ ] I have thoroughly tested my changes
• [x] The change is following the coding conventions
• [x] I have signed the Eclipse Contributor Agreement (ECA)

[HannesWell]

Wait to merge till JDT Core API is merged.

Yes. As it was mentioned in https://github.com/eclipse-jdt/eclipse.jdt.core/pull/2770#issuecomment-2271841269, this cannot be submitted with a fully green built since the changed API would have to be made available through an I-Build, but that cannot pass without this change.

[stephan-herrmann]

This change needs to be merged into BETA_JAVA23

[stephan-herrmann]

This change needs to be merged into BETA_JAVA23

Done in https://github.com/eclipse-jdt/eclipse.jdt.debug/commit/5c13046078fc675645d8c4eb760bcf79ffa9d06d