[stellar/stellar-core] Refactored BucketListIsConsistentWithDatabaseTests for clarity (#1761)

You can view, comment on, or merge this pull request online at:

https://github.com/stellar/stellar-core/pull/1761

— Commit Summary —

* Refactored BucketListIsConsistentWithDatabaseTests for clarity

— File Changes —

M src/invariant/BucketListIsConsistentWithDatabaseTests.cpp (920)

— Patch Links —

https://github.com/stellar/stellar-core/pull/1761.patch
https://github.com/stellar/stellar-core/pull/1761.diff