qa: update test_pmfg.py to use sample metrics for live testing
qa: update test_pmfg.py to use sample metrics for live testing

Also reduced the test runtime and removed comment re prefering
to use non-sample metrics.  Test can now run on all platforms.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp