Moved some dummy function implementations to from ic-x64.cc to stub-cache-x64.cc (where they belong)

Review URL: http://codereview.chromium.org/159404


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2546 ce2b1a6d-e550-0410-aec6-3dcde31c8c00