Remove calls to heapsize (#10432)

* update memorydb trait
* use malloc_size_of instead of heapsize_of
* use jemalloc as default allocator for parity client.

ethcore/src/spec/spec.rs

@@ -813,7 +813,7 @@ impl Spec {
 
 	/// Ensure that the given state DB has the trie nodes in for the genesis state.
 	pub fn ensure_db_good<T: Backend>(&self, db: T, factories: &Factories) -> Result<T, Error> {
-		if db.as_hash_db().contains(&self.state_root()) {
+		if db.as_hash_db().contains(&self.state_root(), hash_db::EMPTY_PREFIX) {
 			return Ok(db);
 		}