Following on from WT-5354, verify now has the functionality to verify the history store against the current state of the data store. 

The purpose of this ticket is to decide upon and accomplish the best way to utilise this functionality.

The proposed solution is to:

• Verify history store every time when we call verify. When given a uri limit the history store verification to that btree
• Add an option to verify just the history store in itself.

TODOs:

• Rework on the API: add history_store as an option to verify
  • Note, while the history store is one file, it is conceptually linked to many objects in our database and thus verifying it independently means verifying all other parts of the database. This is the current implementation and thus will need to be modified or expanded upon to be more specific. After verifying the object itself, we should walk the history store but just the portions relevant for the btree-id from the object.
• Update documentation
  • Currently the documentation is written in favour of the old API implementation (See wiredtiger.in). However, command-line.dox is ambiguous in regards to how the history-store only verification interacts with the uri argument. This documentation needs to be unified. 
    • wiredtiger.in
    • command-line.dox