pmc: convert native to jsonl and track TSC value of samples

pmc: convert native to jsonl and track TSC value of samples

- add '-j' options to filter to enable converting native pmc
  log format to json lines format to enable the use of scripts
  and external tooling

% pmc filter -j pmc.log pmc.jsonl

- Record the tsc value in sampling interrupts as opposed to
  recording nanotime when the sample is copied to a global log
  in hardclock - potentially many milliseconds later.

- At initialize record the tsc_freq and the time of day to give
  us an offset for translating the tsc values in callchain records