Summary:
buf_offset does not need to get the value from req.len for othe final block. It can cause test fail for clan_analyze. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6204
Test Plan: pass make asan_check
Differential Revision: D19145335
Pulled By: zhichao-cao
fbshipit-source-id: 8f6e74565746381b5c5ef598b97d746517b36e5b