Add getter/setter for ID_enumeration in java_class_typet

[jeannielynnmoulton]

Adding getter/setter to avoid direct irept access

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[kroening]

Assuming that this is to determine that a class is an enum type, why not simply check that the base is java.lang.enum?

[jeannielynnmoulton]

This is very much possible. There are a few places where we check get_bool(ID_enumeration) from a typet, so I thought that it might be more elegant to have the solution here than to check the base each time (or create a function outside of JBMC that does it)

[antlechner]

@jeannielynnmoulton Some of those checks might have been added by me. I actually started with checks for "is the base java.lang.Enum" and at some point it was requested in a review to check the ID_enumeration instead, but I don't know if one way would really be better than the other.

[thomasspriggs]

👍 An improvement. It would be nice if we had a catch test that checked the flag is set properly in the parsing and class conversion.