Revert "Implement simple effect typing for variables" and "Handle switch effects".

This reverts r15776 and r15777 due to compile failures on Chromium Mac bots.

TBR=rossberg@chromium.org

Review URL: https://codereview.chromium.org/19482016

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15786 ce2b1a6d-e550-0410-aec6-3dcde31c8c00