Summary:
Handle file boundaries `FileMetaData.smallest`, `FileMetaData.largest` for when `persist_user_defined_timestamps` is false:
    1) on the manifest write path, the original user-defined timestamps in file boundaries are stripped. This stripping is done during `VersionEdit::Encode` to limit the effect of the stripping to only the persisted version of the file boundaries.
    2) on the manifest read path during DB open, a a min timestamp is padded to the file boundaries. Ideally, this padding should happen during `VersionEdit::Decode` so that all in memory file boundaries have a compatible user key format as the running user comparator. However, because the user-defined timestamp size information is not available at that time. This change is added to `VersionEditHandler::OnNonCfOperation`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11578

Test Plan:
```
make all check
./version_edit_test --gtest_filter="*EncodeDecodeNewFile4HandleFileBoundary*".
./db_with_timestamp_basic_test --gtest_filter="*HandleFileBoundariesTest*"
```

Reviewed By: pdillinger

Differential Revision: D47309399

Pulled By: jowlyzhang

fbshipit-source-id: 21b4d54d2089a62826b31d779094a39cb2bbbd51