Change Kerberos test runner default to use TCP rather than UDP (#5930)

* Default Adoptium krb5.conf to use TCP rather than UDP to avoid Firewall issues

Signed-off-by: Andrew Leonard <anleonar@redhat.com>

* Default Adoptium krb5.conf to use TCP rather than UDP to avoid Firewall issues

Signed-off-by: Andrew Leonard <anleonar@redhat.com>

---------

Signed-off-by: Andrew Leonard <anleonar@redhat.com>

jck/jtrunner/config/default/krb5.conf

@@ -10,10 +10,12 @@
 # 3. The values in the copied file must be updated to reflect the server set up.
 # The tests default to using 'default' as the config name.  If another name is used it must be
 # supplied to the test at run time - see opemjdk.test.jck/docs/README.md for more details.
+# 4. Use TCP rather than UDP to avoid auth login problems: https://github.com/adoptium/aqa-tests/issues/5929
 #----------------------------------------------------------------------------------
 
 [libdefaults]
 	default_realm = ADOPTIUM_NET
+	udp_preference_limit = 1
 
 [realms]
 	ADOPTIUM_NET = {