Validate GraalPy ABI suffixes (#19805)
## Summary
Prior to this change, the GraalPy ABI parser discarded the final tag
segment, so an invalid tag like `graalpy240_310_wrong` was accepted and
normalized to `graalpy240_310_native`.
This requires GraalPy ABI tags to end in exactly `_native` and rejects
unexpected or additional suffixes. It adds regression coverage for both
forms.
