Revert "DevTools: [Audits] Fix the way the category counter is updated"

This reverts commit d046ab1672b33b75cbbb394898c43068e3e43772.

BUG=270028
TBR=pfeldman,apavlov@chromium.org

Review URL: https://codereview.chromium.org/22875038

git-svn-id: svn://svn.chromium.org/blink/trunk@156564 bbb929c8-8fbe-4397-9dbb-9b2b20218538