8034943: Eliminate Keberos dependency on com.sun.security.auth to avoid circular dependency

[Alan Bateman]

As part of preparing the JDK for modules we need to look at the 
dependencies between Kerberos and JAAS as they are logically separate 
components.

As it stands we have a circular dependency due to the JDK-specific API 
to JAAS have API dependencies on Kerberos types, and the JGSS 
implementation using one of the CallbackHandlers defined in JDK-specific 
API to JAAS.

I'd like to eliminate this dependency with the following patch:

http://cr.openjdk.java.net/~alanb/8034943/webrev/

It basically copies TextCallbackHandler to 
sun.security.util.ConsoleCallbackHandler and changes TextCallbackHandler 
so that it just delegates to ConsoleCallbackHandler. This is good enough 
to fix the dependency issue and with the change then all the existing 
JAAS and Kerberos tests in the jdk repository pass as before.

-Alan.