Include trx state in query profiling (and DBPerformance log)

* Replaced use of spl hash with random transaction IDs.
  These can be correlated better and make the DBPerformance
  log easier to make sense of. They are also shorter.

Change-Id: I5f49c0d0c26e37807341bbc83b1b41b124164419
Merge "Include trx state in query profiling (and DBPerformance log)"