Turn Load/StoreGlobal into a handler.

BUG=
R=ulan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/26968004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17550 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remove DisallowHeapAllocation requirement now that the target() is cached on the IC.

R=ulan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/61773004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17551 ce2b1a6d-e550-0410-aec6-3dcde31c8c00