Merge move_fn_closure run-passtest into closure-drop

Author: oli-obk

tests/run-pass/closure-drop.rs

@@ -26,5 +26,15 @@ fn main() {
         f(g);
     }
     assert!(ran_drop);
+    ran_drop = false;
+    {
+        let x = Foo(&mut ran_drop);
+        // this closure never by val uses its captures
+        // so it's basically a fn(&self)
+        // the shim used to not drop the `x`
+        let x = move || { let _ = x; };
+        f(x);
+    }
+    assert!(ran_drop);
 }