fixup! Add tests for TemporaryNodeFailure and RequiredNodeFeatureMissing

Author: alecchendev

lightning/src/ln/functional_tests.rs

@@ -3394,7 +3394,6 @@ fn do_test_fail_htlc_backwards_with_reason(failure_code: FailureCode) {
 
 	expect_pending_htlcs_forwardable!(nodes[1]);
 	expect_payment_claimable!(nodes[1], payment_hash, payment_secret, payment_amount);
-	// let failure_code = FailureCode::IncorrectOrUnknownPaymentDetails;
 	nodes[1].node.fail_htlc_backwards_with_reason(&payment_hash, &failure_code);
 
 	expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash: payment_hash }]);