Use construct_runtime in tests (#8059)

* impl some more

* add serde

* remove unused

* fix staking fuzz

* fix system bench

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

substrate/frame/grandpa/src/tests.rs

@@ -19,7 +19,7 @@
 
 #![cfg(test)]
 
-use super::{Call, *};
+use super::{Call, Event, *};
 use crate::mock::*;
 use codec::{Decode, Encode};
 use fg_primitives::ScheduledChange;