We do not know if we are going to need it and creating it lazyly might cause us to insert it at the block that does not dominate all uses.

R=mstarzinger@chromium.org
TEST=mjsunit/compiler/inline-arguments.js

Review URL: https://chromiumcodereview.appspot.com/9692046

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11024 ce2b1a6d-e550-0410-aec6-3dcde31c8c00