message: [storage] modify unit test remove redundance cache storage
diff: // Copyright (c) The Starcoin Core Contributors
  // SPDX-License-Identifier: Apache-2.0
  -use crate::cache_storage::CacheStorage;
  use crate::db_storage::DBStorage;
  use crate::storage::StorageInstance;
  use crate::Storage;
  @@ -13,9 +12,7 @@ use std::sync::Arc;
  #[test]
  fn test_storage() {
  - // let cache_storage = Arc::new(CacheStorage::new());
  - let tmpdir = libra_temppath::TempPath::new();
  - let db_storage = Arc::new(DBStorage::new(tmpdir.path()));
  + let db_storage = Arc::new(DBStorage::new(starcoin_config::temp_path().as_ref()));
  let storage = Storage::new(StorageInstance::new_db_instance(db_storage)).unwrap();
  let acc_node = AccumulatorNode::new_leaf(NodeIndex::new(1), HashValue::random());
  