Moves all test runtimes to use derive_impl (#2409)

Step in https://github.com/paritytech/polkadot-sdk/issues/171

This PR adds `derive_impl` on all `frame_system` config impls for mock
runtimes. The overridden configs are maintained as of now to ensure
minimal changes.

---------

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/frame/examples/dev-mode/src/tests.rs

@@ -18,7 +18,7 @@
 //! Tests for pallet-dev-mode.
 
 use crate::*;
-use frame_support::{assert_ok, traits::ConstU64};
+use frame_support::{assert_ok, derive_impl, traits::ConstU64};
 use sp_core::H256;
 use sp_runtime::{
 	traits::{BlakeTwo256, IdentityLookup},
@@ -39,6 +39,7 @@ frame_support::construct_runtime!(
 	}
 );
 
+#[derive_impl(frame_system::config_preludes::TestDefaultConfig as frame_system::DefaultConfig)]
 impl frame_system::Config for Test {
 	type BaseCallFilter = frame_support::traits::Everything;
 	type BlockWeights = ();