improve iterator randomization
Add a commented out warning and a way for diag.t to ignore it
improve how Devel::Peek::Dump handles iterator information

* If the hash is not OOK omit any iterator status information
  instead of showing -1/NULL
* If the hash is OOK then add the RAND value from the iterator
  and if the LASTRAND is not the same show it too
* Tweak tests to test the above.