Ensuring benchmark.py works correctly in SymmetricMPI mode.

Also cleaning up some API/usage. bechmark.py now dumps out timerlog on each
process in symmetric-mpi mode, with correct process ranks displayed.

Change-Id: I03fad04d63059af11d91c064f726fbbbe90d9c46
Merge topic 'clean_coprocessing_python' into next

42d4671 Ensuring benchmark.py works correctly in SymmetricMPI mode.