DevTools: Never bring up suggest box on Esc

R=eustas, pfeldman, vsevik
BUG=340988
NOTRY=true

Review URL: https://codereview.chromium.org/143283013

git-svn-id: svn://svn.chromium.org/blink/trunk@171138 bbb929c8-8fbe-4397-9dbb-9b2b20218538