Introduce code_substitute (#8898)

This introduces a new field `code_substitute` into the chain spec. This
can be used to substitute the on-chain wasm starting from a given block
until there is another wasm on chain (determined through the
`spec_version`). This can be used to fix broken on chain wasm runtimes.

substrate/bin/node/testing/src/client.rs

@@ -32,7 +32,7 @@ pub type Backend = sc_client_db::Backend<node_primitives::Block>;
 /// Test client type.
 pub type Client = client::Client<
 	Backend,
-	client::LocalCallExecutor<Backend, Executor>,
+	client::LocalCallExecutor<node_primitives::Block, Backend, Executor>,
 	node_primitives::Block,
 	node_runtime::RuntimeApi,
 >;
@@ -63,7 +63,7 @@ pub trait TestClientBuilderExt: Sized {
 
 impl TestClientBuilderExt for substrate_test_client::TestClientBuilder<
 	node_primitives::Block,
-	client::LocalCallExecutor<Backend, Executor>,
+	client::LocalCallExecutor<node_primitives::Block, Backend, Executor>,
 	Backend,
 	GenesisParameters,
 > {