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/elections-phragmen/src/lib.rs

@@ -1307,7 +1307,7 @@ mod tests {
 	use super::*;
 	use crate as elections_phragmen;
 	use frame_support::{
-		assert_noop, assert_ok,
+		assert_noop, assert_ok, derive_impl,
 		dispatch::DispatchResultWithPostInfo,
 		parameter_types,
 		traits::{ConstU32, ConstU64, OnInitialize},
@@ -1321,6 +1321,7 @@ mod tests {
 	};
 	use substrate_test_utils::assert_eq_uvec;
 
+	#[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 = ();