Implement HChange support for Smis and use it in Load/StoreNameField

BUG=
R=verwaest@chromium.org

Review URL: https://chromiumcodereview.appspot.com/15303004

Patch from Daniel Clifford <danno@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14765 ce2b1a6d-e550-0410-aec6-3dcde31c8c00