Various nits and alignments for testnet runtimes (#3024)

There were several improvements and PRs that didn't apply to all
runtimes, so this PR attempts to align those small differences. In
addition, the PR eliminates unused dependencies across multiple modules.

Relates to PR for `polkadot-fellows`:
https://github.com/polkadot-fellows/runtimes/pull/154

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/Cargo.toml

@@ -18,7 +18,6 @@ hex-literal = { version = "0.4.1" }
 log = { version = "0.4.20", default-features = false }
 scale-info = { version = "2.10.0", default-features = false, features = ["derive"] }
 serde = { version = "1.0.195", optional = true, features = ["derive"] }
-smallvec = "1.11.0"
 
 # Substrate
 frame-benchmarking = { path = "../../../../../substrate/frame/benchmarking", default-features = false, optional = true }
@@ -57,7 +56,6 @@ sp-version = { path = "../../../../../substrate/primitives/version", default-fea
 westend-runtime-constants = { path = "../../../../../polkadot/runtime/westend/constants", default-features = false }
 pallet-xcm = { path = "../../../../../polkadot/xcm/pallet-xcm", default-features = false }
 pallet-xcm-benchmarks = { path = "../../../../../polkadot/xcm/pallet-xcm-benchmarks", default-features = false, optional = true }
-polkadot-core-primitives = { path = "../../../../../polkadot/core-primitives", default-features = false }
 polkadot-parachain-primitives = { path = "../../../../../polkadot/parachain", default-features = false }
 polkadot-runtime-common = { path = "../../../../../polkadot/runtime/common", default-features = false }
 xcm = { package = "staging-xcm", path = "../../../../../polkadot/xcm", default-features = false }
@@ -156,7 +154,6 @@ std = [
 	"pallet-xcm/std",
 	"parachain-info/std",
 	"parachains-common/std",
-	"polkadot-core-primitives/std",
 	"polkadot-parachain-primitives/std",
 	"polkadot-runtime-common/std",
 	"scale-info/std",
@@ -249,5 +246,5 @@ experimental = ["pallet-aura/experimental"]
 
 # A feature that should be enabled when the runtime should be built for on-chain
 # deployment. This will disable stuff that shouldn't be part of the on-chain wasm
-# to make it smaller like logging for example.
+# to make it smaller, like logging for example.
 on-chain-release-build = ["sp-api/disable-logging"]

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

@@ -508,13 +508,9 @@ bridge_runtime_common::generate_bridge_reject_obsolete_headers_and_messages! {
 	BridgeRococoMessages
 }
 
-#[cfg(feature = "runtime-benchmarks")]
-#[macro_use]
-extern crate frame_benchmarking;
-
 #[cfg(feature = "runtime-benchmarks")]
 mod benches {
-	define_benchmarks!(
+	frame_benchmarking::define_benchmarks!(
 		[frame_system, SystemBench::<Runtime>]
 		[pallet_balances, Balances]
 		[pallet_message_queue, MessageQueue]