Revert "Test for returning Failure objects from PL/Perl6"

This reverts commit 767e473.
There is a failure branch tracking this now. Let's hope it isn't
aptly named.

t/sql/plperl6.sql

@@ -25,10 +25,6 @@ CREATE OR REPLACE FUNCTION test_mu() RETURNS void LANGUAGE plperl6 AS $$
 { Mu }
 $$;
 
-CREATE OR REPLACE FUNCTION test_return_failure() RETURNS void LANGUAGE plperl6 AS $$
-{ Failure }
-$$;
-
 CREATE OR REPLACE FUNCTION test_int_plperl6() RETURNS int LANGUAGE plperl6 AS $$
 () { 42 }
 $$;
@@ -200,8 +196,6 @@ select is(test_global_grammar(''), 0, 'empty string should not parse in the glob
 
 SELECT language_is_trusted( 'plperl6', 'PL/Perl6 should be trusted' );
 
-select is(test_return_failure()::text,'', 'Return Failure from PL/Perl6');
-
 -- Finish the tests and clean up.
 SELECT * FROM finish();