Add TreeDiff trait to reuse tree functions (#11046) (#11048)

Co-authored-by: Carl <carl@solana.com>
(cherry picked from commit e9cbdf711b)

Co-authored-by: carllin <wumu727@gmail.com>

core/src/lib.rs

@@ -63,6 +63,7 @@ pub mod sigverify_stage;
 pub mod snapshot_packager_service;
 pub mod tpu;
 pub mod transaction_status_service;
+pub mod tree_diff;
 pub mod tvu;
 pub mod validator;
 pub mod verified_vote_packets;