Revert "Upgrade to perfcascade-2.8.0 (#3325)" (#3330)
Revert "Upgrade to perfcascade-2.8.0 (#3325)" (#3330)

This reverts commit d91a2a14a6eb22b2603f189d65203f355b70548b.
sitespeedio/sitespeed.io,sitespeedio/sitespeed.io,sitespeedio/sitespeed.io,sitespeedio/sitespeed.io