ENG-4981: Only write writes to the repair log.
ENG-4981: OrderableTransaction doesn't use SP handle and there is only
one meaningful subclass.  Pull sphandle up into TransactionState.
ENG-4981: Aside, don't need Iv2 prefix on tests any longer.  Fix this
one since we're about to monkey with it.
ENG-4981: Let the mailbox send(array, msg) call do the iterating for
us.  Also, provides a consistent interface usage for mockito probing.
ENG-4981: Add initial test to validate the SP handle sequence
generated by the SPI master.
ENG-4981: Add a fuzz test for RepairLog validation
ENG-4981: Add a fuzz test for SP repair
ENG-4981: Add fuzz testing for MpPromoteAlgo.