GitLab

Details:
- avoid use of system() in favor of fork/exec.
- add option to selectively disable/enable mpdecision service around perf
  collection runs to improve profile quality and avoid kernel pmuevents issues.
- default to using 'simpleperf' instead of 'perf'

Change-Id: I27928d8bb647fd852ec944158ebfd8efa38c01b4