State metrics possible changes (#5168)

* Registering state from overlay.

* fix

* fix2

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/primitives/state-machine/src/changes_trie/build.rs

@@ -469,6 +469,7 @@ mod test {
 				].into_iter().collect(),
 			},
 			collect_extrinsics: true,
+			stats: Default::default(),
 		};
 		let config = Configuration { digest_interval: 4, digest_levels: 2 };