Anonymize AbstractRefCounted (#77208)

Today `AbstractRefCounted` has a `name` field which is only used to
construct the exception message when calling `incRef()` after it's been
closed. This isn't really necessary, the stack trace will identify the
reference in question and give loads more useful detail besides. It's
also slightly irksome to have to name every single implementation.

This commit drops the name and the constructor parameter, and also
introduces a handy factory method for use when there's no extra state
needed and you just want to run a method or lambda when all references
are released.

plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AmazonEc2Reference.java

@@ -22,7 +22,6 @@ public class AmazonEc2Reference extends AbstractRefCounted implements Releasable
     private final AmazonEC2 client;
 
     AmazonEc2Reference(AmazonEC2 client) {
-        super("AWS_EC2_CLIENT");
         this.client = client;
     }