Crankshaft is now the default on all platforms. This is the first
patch on the way to removing the classic code generator from the
system.

R=kmillikin@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/6771045

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7469 ce2b1a6d-e550-0410-aec6-3dcde31c8c00