- Call_provers.parse_prover_run does not attempt fixing answer anymore,
  except in the case where the answer is HighFailure and time is close
  to time limit (which is considered as Timeout)

- Session_scheduler.fuzzy_proof_time is now more liberal, accepts
  that two answers Unknown or Timeout of OutOfMemory with less than
  10% difference in time are equivalent, and thus should not be
  reported as a significant change