Make offences benchmark runnable (paritytech#10782)

* Make offences benchmark runnable

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* cargo run --quiet --profile=production  --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_offences --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/offences/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Revert bench-bot

This reverts commit 73d0cb2.

Co-authored-by: Parity Bot <admin@parity.io>

frame/offences/benchmarking/src/lib.rs

@@ -405,6 +405,7 @@ benchmarks! {
 	}
 	verify {
 		// make sure that all slashes have been applied
+		#[cfg(test)]
 		assert_eq!(
 			System::<T>::event_count(), 0
 			+ 1 // offence
@@ -440,6 +441,7 @@ benchmarks! {
 	}
 	verify {
 		// make sure that all slashes have been applied
+		#[cfg(test)]
 		assert_eq!(
 			System::<T>::event_count(), 0
 			+ 1 // offence