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/basic/src/tests.rs

@@ -19,7 +19,7 @@
 
 use crate::*;
 use frame_support::{
-	assert_ok,
+	assert_ok, derive_impl,
 	dispatch::{DispatchInfo, GetDispatchInfo},
 	traits::{ConstU64, OnInitialize},
 };
@@ -45,6 +45,7 @@ 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 = ();