test_cpu_characterization.py not passing all cases

[bgeltz]

Describe the bug
I tried to run test_cpu_characterization.py and I expected it to pass instead it fails for the minife portion and passes for the AIB portion though that may not be expected.

GEOPM version
TBD

Expected behavior
Test passes all assertions.
Feff is expected to be above minimum and below maximum achievable frequencies on the target system.

Frequency setting for the activity agent should never be below Feff for any Phi value. This should be a new test assertion.

Actual behavior
Current runs are showing that Feff is being set to max many core turbo which seems to be an error.
Running AIB intensity 1 with the CA agent shows that the achieved frequency is significantly below the Feff.

Examining the CPU frequency sweeps that were used for characterization:
AIB at intensity 1 (memory intensive) shows expected behavior with frequency sweeps -> increased energy consumption with increased frequency.

AIB at intensity 16 (CPU intensive) shows expected behavior with frequency sweeps-> decreased energy consumption with increased frequency.