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/Cargo.lock

@@ -1644,6 +1644,7 @@ dependencies = [
  "linregress",
  "parity-scale-codec",
  "paste 1.0.4",
+ "serde",
  "sp-api",
  "sp-io",
  "sp-runtime",
@@ -4730,6 +4731,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "parity-scale-codec",
+ "serde",
  "sp-core",
  "sp-io",
  "sp-runtime",
@@ -5150,6 +5152,7 @@ dependencies = [
  "pallet-staking-reward-curve",
  "pallet-timestamp",
  "parity-scale-codec",
+ "serde",
  "sp-core",
  "sp-io",
  "sp-npos-elections",