DevTools: bring back filter status in console

Console used to have filter status with text "%d messages are
hidden by filters. Show all messages." This was missed somewhere
in M36, and this patch brings this back.

Review URL: https://codereview.chromium.org/239433003

git-svn-id: svn://svn.chromium.org/blink/trunk@171762 bbb929c8-8fbe-4397-9dbb-9b2b20218538