Bug #11766854 addendum :

Fixed test suite failures when the auth plugin is not compiled in.

mysql-test/include/have_plugin_auth.inc

@@ -2,3 +2,4 @@ disable_query_log;
 --require r/true.require
 select (PLUGIN_LIBRARY LIKE 'auth_test_plugin%') as `TRUE` FROM INFORMATION_SCHEMA.PLUGINS 
   WHERE PLUGIN_NAME='test_plugin_server';
+enable_query_log;

mysql-test/t/mysql_client_test-master.opt

---log=$MYSQLTEST_VARDIR/log/master.log --log-output=FILE,TABLE
+--log=$MYSQLTEST_VARDIR/log/master.log 
+--log-output=FILE,TABLE
+$PLUGIN_AUTH_OPT
+$PLUGIN_AUTH_LOAD

mysql-test/t/mysql_client_test.test

 # This test should work in embedded server after we fix mysqltest
 -- source include/not_embedded.inc
+# need to have the dynamic loading turned on for the client plugin tests
+--source include/have_plugin_auth.inc
 
 SET @old_general_log= @@global.general_log;
 SET @old_slow_query_log= @@global.slow_query_log;