support for value classes

[Ladicek]

On the API level, this likely means just adding ClassInfo.isValue() (or isValueClass()). However, this also involves changing the serialization format.

Per https://openjdk.org/jeps/401:

Whether a class is an identity class or a value class is recorded in its class file. Identity classes have the ACC_IDENTITY flag set; value classes do not. This flag supersedes the legacy ACC_SUPER flag. The JVM Specification always recommended that compilers and tools set the ACC_SUPER flag in class files, so by default, compilers and tools can continue to set the flag in new class files and generate identity classes.

[Ladicek]

I'm not targeting this to any particular release, but I'm fairly sure this isn't needed any time soon.