DevTools: Optionally disable the node info tooltip when hovering elements

Pressing Ctrl/Cmd when hovering elements in the console/DOM tree
will inhibit the tooltip.

R=eustas, pfeldman, vsevik
BUG=282493

Review URL: https://codereview.chromium.org/269813004

git-svn-id: svn://svn.chromium.org/blink/trunk@173375 bbb929c8-8fbe-4397-9dbb-9b2b20218538