Fix Snowbridge benchmark tests (paritytech#7296)

Related to:
paritytech#7295 (comment)

---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Adrian Catangiu <adrian@parity.io>

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/lib.rs

@@ -394,10 +394,14 @@ parameter_types! {
 impl pallet_message_queue::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type WeightInfo = weights::pallet_message_queue::WeightInfo<Runtime>;
-	#[cfg(feature = "runtime-benchmarks")]
+	// Use the NoopMessageProcessor exclusively for benchmarks, not for tests with the
+	// runtime-benchmarks feature as tests require the BridgeHubMessageRouter to process messages.
+	// The "test" feature flag doesn't work, hence the reliance on the "std" feature, which is
+	// enabled during tests.
+	#[cfg(all(not(feature = "std"), feature = "runtime-benchmarks"))]
 	type MessageProcessor =
 		pallet_message_queue::mock_helpers::NoopMessageProcessor<AggregateMessageOrigin>;
-	#[cfg(not(feature = "runtime-benchmarks"))]
+	#[cfg(any(feature = "std", not(feature = "runtime-benchmarks")))]
 	type MessageProcessor = bridge_hub_common::BridgeHubMessageRouter<
 		xcm_builder::ProcessXcmMessage<
 			AggregateMessageOrigin,