[FLE] Add a corpus test that exhaustively enumerates all ways to encrypt all BSON value types

Description of Drivers Ticket:

A new spec "corpus" test was added, where each driver constructs a document with encryption along all of these axes, producing a document like this, which we can make assertions on (deterministic explicit matches automatic, random differs, all can be explicitly decrypted, etc.).

Creating tickets only for C#, Go, Java and Python as implementation of the FLE spec is in progress and rest of the drivers have not started.
See DRIVERS-686 for updated details.