Summary:
Unity build fails because of name conflict of IsFileSectorAligned() after recent refactoring. Consolidate the function.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5812
Test Plan: make unity. At least the failure goes away. Also "make all", "make release" and see no regression in normal cases.
Differential Revision: D17411403
fbshipit-source-id: 09d5653471ae2c3a4d898e120a024f7dd08d9c9d