DevTools: Revert stepping over/out on a call frame backend code.

This code is unused.

R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/333153003

git-svn-id: svn://svn.chromium.org/blink/trunk@176464 bbb929c8-8fbe-4397-9dbb-9b2b20218538