RFR [14] 8234782: Discuss evolution of records in serialization spec

[Chris Hegarty]

As raised in the CSR feedback for records [1], evolution of serializable
records should be discussed in the updates to the serialization spec.

The most significant aspects of serialization evolution concerning
records are 1) adding and removing record components, and 2) the
compatible scenarios where an ordinary class may be changed to a record
class. The following is a proposal to address both.

Spec changes:
  https://cr.openjdk.java.net/~chegar/records/spec/records-serialization-addendum.html

CSR:
  https://bugs.openjdk.java.net/browse/JDK-8237202
  
-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-8233436