Summary:
The patch makes sure that the functionality required for the new integrated
BlobDB implementation (most importantly, the classes related to reading and
writing blob files) is also built in LITE mode by removing the corresponding
`#ifndef`s.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7272

Test Plan: Ran `make check` in both regular and LITE mode.

Reviewed By: zhichao-cao

Differential Revision: D23173280

Pulled By: ltamasi

fbshipit-source-id: 1596bd1a76409a8a6d83d8f1dbfe08bfdea7ffe6