Aligning internal GraalVM versioning with JDK versions

[alina-yur]

At the moment, GraalVM uses both JDK versioning (GraalVM for JDK 22, GraalVM for JDK 23, ...) and our internal versioning (GraalVM for JDK 22 = GraalVM v24.0, GraalVM for JDK 23 = v24.1). To better align with JDK releases, and also to avoid confusion, we will slow down our versioning for one release, so that we can catch up with JDK versioning starting with JDK 25.

The change will work as follows:

GraalVM version	Java version
24.1	23
24.2	24
25.0	25
26.0	26

So the key change is that GraalVM for JDK 24 will have internal version 24.2, and starting with GraalVM for JDK 25 in September 2025 the versions will be fully aligned. The new versioning will also apply to Truffle and Graal languages.

If you are integrating with GraalVM, or tracking internal versions, please adjust for this change.