Align ClassFileClassMetadata with other implementations

[philwebb]

Return null for getSuperClassName() with package-info classes:

Upgrading Spring Boot to use Framework 7 hit an issue with spring-hateoas and AOT hints.

at org.springframework.aot.hint.SimpleTypeReference.of(SimpleTypeReference.java:47)	
	at org.springframework.aot.hint.TypeReference.of(TypeReference.java:85)	
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:215)	
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:215)	
	at java.util.Iterator.forEachRemaining(Iterator.java:133)	
	at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1939)	
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:570)	
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:560)	
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:153)	
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:176)	
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265)	
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:636)	
	at org.springframework.hateoas.aot.AotUtils.registerTypesForReflection(AotUtils.java:109)

This is ultimately caused by a change in behavior when running on Java 24. With earlier versions, the registerTypesForReflection uses a scanner that uses a SimpleAnnotationMetadataReader. This scanner always returns null for getSuperClassName() results from package-info classes. It appears that ClassFileClassMetadata returns Object.class.

This seems like a possible bug in the new class file Java API, but I think we should add a workaround in our code as well.

[philwebb]

I found another quirk with member classes so I've added a second commit to this PR.

[bclozel]

Thanks @philwebb !