Bootstrapper::CreateEnvironment() returns a global handle to the created context so there is no need to create another one explicitly.

BUG=v8:1006

Review URL: http://codereview.chromium.org/6048003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6092 ce2b1a6d-e550-0410-aec6-3dcde31c8c00