DevTools: [Audits] Do not report external CSS file inclusion order violation when no such error exists

R=eustas
BUG=295552

Review URL: https://chromiumcodereview.appspot.com/23726047

git-svn-id: svn://svn.chromium.org/blink/trunk@158177 bbb929c8-8fbe-4397-9dbb-9b2b20218538