fix librustc_driver

Author: nikomatsakis

src/librustc_driver/test.rs

@@ -141,6 +141,7 @@ fn test_env<F>(source_string: &str,
     TyCtxt::create_and_enter(&sess,
                              ty::maps::Providers::default(),
                              ty::maps::Providers::default(),
+                             Rc::new(sess.mir_passes.borrow().clone()),
                              &arenas,
                              &arena,
                              resolutions,