Trim js.complexityReports output size

[msiebuhr]

Currently the js.complexityReport output 16 different metrics, both under "functions" and "aggregate" (16×2 = 32), whereon we calculate count, mean, max, std, mean_90th and max_90th (32×6 = 192 metrics).

My gut feelig is that at least one of "functions" or "aggregate" shoulb be canned.