logcat: test: modernize

- split sequential sort output test out as a benchmark check
- Allow up to two failures of sort results because of occasional reader locks.
- logcat -g output was changed to handle wider set of values incorporating a
  multiplier for UX, and would not pass test if 'logcat -G 1M' was run.
- If spam filter is turned off, prune checks would fail, allowed for an
  empty default.

Change-Id: I06d6089e18279df7525d1c16a1f76b3125ddbf05