remove equality kind from compare nil ic

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15042 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
also remove the constant

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15043 ce2b1a6d-e550-0410-aec6-3dcde31c8c00