This is just a cleanup work to hide some of the private state of
ReplSetTest so it is easier to encapsulate and add new logic. Also enables
strict mode.
As a temporary compatibility measure, the legacy behavior is preserved
if the "cursor" option is not sent with the command. This
compatibility layer will be removed as part of work for the parent
ticket.
Non-replicated hosts still drop temp collections on startup. This is
inappropriate for replica set members (and pure slaves) since it can lead to
discrepancies between hosts.
