Revert and redo #952 (#1133)

* Revert "Pruning changes trie without digests (#952)"

This reverts commit 6f9a505fba.

* pruning changes tries without digests

* u64::max_value()

* Update wasm files and fix merge conflict

* Fixes tests

substrate/node/executor/Cargo.toml

@@ -29,3 +29,6 @@ srml-timestamp = { path = "../../srml/timestamp" }
 srml-treasury = { path = "../../srml/treasury" }
 srml-contract = { path = "../../srml/contract" }
 wabt = "0.4"
+
+[features]
+benchmarks = []