by adding NearLabel's functionality to Label and introducing a "near" parameter to jump instructions.

TEST=compiles; existing tests still pass.

Review URL: http://codereview.chromium.org/6928060

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7832 ce2b1a6d-e550-0410-aec6-3dcde31c8c00