Revert of Make pause-on-exceptions toggle/tri-state button. (https://codereview.chromium.org/102003006/)

Reason for revert:
Temporarily revert to avoid user confusion.

Original issue's description:
> Make pause-on-exceptions toggle/tri-state button.
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165051

TBR=vsevik@chromium.org,aandrey@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/145583007

git-svn-id: svn://svn.chromium.org/blink/trunk@165867 bbb929c8-8fbe-4397-9dbb-9b2b20218538