We currently don't plan to support internal transactions/sessions outside of sharded clusters. Add uasserts (similar to this one) in initializeOperationSessionInfo(), the SessionCatalog and the LogicalSessionCache to enforce this. As part of this ticket, we will need to:

• Update jstests/multiVersion/internal_sessions.js to use ShardingTest instead ReplSetTest (see jstests/multiVersion/internal_transactions_retry_on_transient_transaction_error.js for an example)
• Make jstests/replsets/internal_sessions_reaping.js use ShardingTest instead of ReplSetTest and move it to jstests/sharding.