Benchmark Staking and Session Pallet (#5183)

* starting bench

* More

* more

* Payout Validator

* Give each validator exactly n nominators

* Update with test

* Try to add accounts to chain spec

* Undo changes to chainspec

* Payout nominator

* Rebond and Reap Stash

* Set history depth

* fix smelly code

* cancel deferred slash

* new_era bench

* do_slash benchmark

* Add features

* undo extrinsic move

* lower

* Update new era

* Update benchmarking.rs

* whitespace

* Apply suggestions from code review

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* fixes

* nit

* Refactor tests, initial code

* Move session benchmarks to avoid cyclic deps

* Update lib.rs

* Fix warnings

* Move impl

* Update to do random nominator allocation

* add feature to benchmark pallet

* Remove extra stuff

* Update based on feedback

* Less intrusive

* Remove `transfer_idle_users`

* remove again

* unused dep

* test feature flag

* Update to latest substrate

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

substrate/bin/node/runtime/src/lib.rs

@@ -851,6 +851,11 @@ impl_runtime_apis! {
 			repeat: u32,
 		) -> Result<Vec<frame_benchmarking::BenchmarkResults>, sp_runtime::RuntimeString> {
 			use frame_benchmarking::Benchmarking;
+			// Trying to add benchmarks directly to the Session Pallet caused cyclic dependency issues.
+			// To get around that, we separated the Session benchmarks into its own crate, which is why
+			// we need these two lines below.
+			use pallet_session_benchmarking::Module as SessionBench;
+			impl pallet_session_benchmarking::Trait for Runtime {}
 
 			let result = match module.as_slice() {
 				b"pallet-balances" | b"balances" => Balances::run_benchmark(
@@ -867,6 +872,20 @@ impl_runtime_apis! {
 					steps,
 					repeat,
 				),
+				b"pallet-session" | b"session" => SessionBench::<Runtime>::run_benchmark(
+					extrinsic,
+					lowest_range_values,
+					highest_range_values,
+					steps,
+					repeat,
+				),
+				b"pallet-staking" | b"staking" => Staking::run_benchmark(
+					extrinsic,
+					lowest_range_values,
+					highest_range_values,
+					steps,
+					repeat,
+				),
 				b"pallet-timestamp" | b"timestamp" => Timestamp::run_benchmark(
 					extrinsic,
 					lowest_range_values,