This allows the test harness to download missing test suite data if
necessary. We use the bzip2 archive for test262 because it is faster
than cloning the repository and also works without any Mercurial
installation.

R=yangguo@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9619002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10955 ce2b1a6d-e550-0410-aec6-3dcde31c8c00