ParentNotInitializedException when using Java 14 switch expressions with cases which have multiple values

[davidog23]

spoon-core version: 8.3.0
Code to reproduce the bug:

import spoon.Launcher;
import spoon.reflect.declaration.CtClass;
import spoon.reflect.declaration.CtElement;

public class A {
    public static void main(String[] args) {
        CtClass l = Launcher.parseClass("class A { { int x = switch(1) { case 1, 3 -> 0; default -> 1}; } }");
        for (CtElement a : l.asIterable()) {
            a.getParent();
        }
    }
}

Exception in thread "main" spoon.reflect.declaration.ParentNotInitializedException: parent not initialized for class spoon.support.reflect.code.CtLiteralImpl (unknown file)
	at spoon.support.reflect.declaration.CtElementImpl.getParent(CtElementImpl.java:366)
	at A.main(A.java:9)

The CtLiteralImpl which represents the number 3 throws a ParentNotInitializedException when getting its parent. I guess that is not intended behaviour.

[MartinWitt]

Fixed by #3689