JDK 14 RFR of JDK-8231368: Suppress warnings on non-serializable non-transient instance fields in java.security.jgss

[Joe Darcy]

Hello,

Another module, another review request as part of making serial warnings 
more robust:

     JDK-8231368: Suppress warnings on non-serializable non-transient 
instance fields in java.security.jgss
     http://cr.openjdk.java.net/~darcy/8231368.0/

(Related earlier review 
https://mail.openjdk.java.net/pipermail/security-dev/2019-September/020672.html.)

In this latest review, I included a comment in KRBError.java that its 
writeObject method uses a different encoding scheme.

Thanks,

-Joe