Introduce more debug events for promises.

BUG=v8:3093
LOG=Y
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/393283007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22591 ce2b1a6d-e550-0410-aec6-3dcde31c8c00