Code cleanup for trace replayer (#8652)

Code cleanup for trace replayer (#8652)

Summary:
- Remove extra `;` in trace_record.h
- Remove some unnecessary `assert` in trace_record_handler.cc
- Initialize `env_` after` exec_handler_` in `ReplayerImpl` to let db be asserted in creating the handler before getting `db->GetEnv()`.
- Update history to include the new `TraceReader::Reset()`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8652

Reviewed By: ajkr

Differential Revision: D30276872

Pulled By: autopear

fbshipit-source-id: 476ee162e0f241490c6209307448343a5b326b37