Summary:
DBTest2.ChangePrefixExtractor fails in LITE build because LITE build doesn't support adaptive build. Fix it by removing the stats check but only check correctness.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6356

Test Plan: Run the test with both of LITE and non-LITE build.

Differential Revision: D19669537

fbshipit-source-id: 6d7dd6c8a79f18e80ca1636864b9c71922030d8e