Merge branch 'latency-rebase-again' of https://github.com/vincentkfu/fio

Merge branch 'latency-rebase-again' of https://github.com/vincentkfu/fio

* 'latency-rebase-again' of https://github.com/vincentkfu/fio:
  t/run-fio-tests: increase time allowed for tests to pass
  t/run-fio-tests: add latency_percentiles.py
  t/latency_percentiles: test latency percentile reporting
  stat: fix high/low prio unified rw bug
  fio: better distinguish between high and low priority
  stat: make priority summary statistics consistent with percentiles
  docs: updates for slat, clat, lat percentile reporting
  gfio: display slat, clat, and lat percentiles
  fio: report percentiles for slat, clat, lat
  fio: groundwork for adding slat, lat percentiles