Objects.newIdentity update

[Dan Smith]

An update on Objects.newIdentity for Java 17: Roger did some work to put the feature together and get it reviewed.

https://bugs.openjdk.java.net/browse/JDK-8269096

However, while the implementation is straightforward, for libraries folks not deeply familiar with the Valhalla Project, the concept of a method that does the same thing as 'new Object()' did not seem particularly justified. I think they're especially uncomfortable with the idea of talking about creating an "identity" in a world in which all objects have identity.

https://bugs.openjdk.java.net/browse/JDK-8269097

So, not going to work out for this release. We made a bet that it would be a simple, noncontroversial matter to slip in an extra method, but it turns out to be a tougher sell than we thought.

Of course, as part of JEP 401, a feature like this will have the surrounding context, with things like the IdentityObject interface, so that it will make a lot more sense. We'll plan for that.