Replace libsecp256k1 with k256 in FRAME related code (#10883)

* Replace libsecp256k1 with k256 in beefy-mmr

* Port of FRAME `contracts` benchmarking from `libsecp256k1` to `k256`

* Newtype to allow `Pcg32` rng usage with `k256` in contracts benchmarks

* Use `sp-io::crypto` to generate dummy keys in `contracts` bechmarks

* More compact code

* Cargo fmt

* Build `sp-keystore` only for dev profile

* Move public key generation back to the `map`

substrate/frame/contracts/src/tests.rs

@@ -43,12 +43,13 @@ use frame_system::{self as system, EventRecord, Phase};
 use pretty_assertions::assert_eq;
 use sp_core::Bytes;
 use sp_io::hashing::blake2_256;
+use sp_keystore::{testing::KeyStore, KeystoreExt};
 use sp_runtime::{
 	testing::{Header, H256},
 	traits::{BlakeTwo256, Convert, Hash, IdentityLookup},
 	AccountId32,
 };
-use std::cell::RefCell;
+use std::{cell::RefCell, sync::Arc};
 
 use crate as pallet_contracts;
 
@@ -328,6 +329,7 @@ impl ExtBuilder {
 			.assimilate_storage(&mut t)
 			.unwrap();
 		let mut ext = sp_io::TestExternalities::new(t);
+		ext.register_extension(KeystoreExt(Arc::new(KeyStore::new())));
 		ext.execute_with(|| System::set_block_number(1));
 		ext
 	}