Ignore live_edit_ flag when when dealing with LiveEdit in a debug break.

LiveEdit maybe disabled when we enter the break and again when we
leave it, but enabled in between.

TEST=https://codereview.chromium.org/329533002
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/325183003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21770 ce2b1a6d-e550-0410-aec6-3dcde31c8c00