JAV2I12 — RMI/IDL Tie changes

Summary: The following changes will improve the code generated for RMI/IDL Ties:

a) RMI/IDL Tie classes shall catch org.omg.CORBA.SystemException and
rethrow it (unwrapped by UnknownException).

b) Change the signature of Util.mapSystemException to
public static java.rmi.RemoteException
mapSystemException(org.omg.CORBA.SystemException ex);

c) RMI/IDL Tie classes shall throw the result from mapSystemException.

d) mapSystemException shall return the mapped exception if it is an
instance of RemoteException or a subclass, and shall throw the
mapped exception in all other cases.

This has been agreed by the RTF, but an OMG issue number is needed.

Closed, accepted (see summary for text)