Add tests verifying session options are passed correctly in CRUD operations

In https://jira.mongodb.org/browse/RUBY-1865 many tests were added for various CRUD options being passed correctly. Unfortunately the session options require more handling:

• Pre-3.6 servers fail when given session argument
• Therefore, session must be conditional on server version
• We do want to assert that sessions are passed in correctly
• We may wish to test that specifying a nil session explicitly in an operation does not pass a session to the server