Introduce new stepping mode to step into another frame.

R=aandrey@chromium.org
BUG=chromium:267592
LOG=Y

Review URL: https://codereview.chromium.org/690263004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25130 ce2b1a6d-e550-0410-aec6-3dcde31c8c00