Merged r13285, r13303 into 3.15 branch.

postmortem: export kSmiShiftSize

Synched postmortem script with not-so-recent changes.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/11743017

git-svn-id: https://v8.googlecode.com/svn/branches/3.15@13305 ce2b1a6d-e550-0410-aec6-3dcde31c8c00