Method overriding tests suddenly pass valgrind for some reason.

I'm not sure if this is because of changes to glue generation in the
last few days while I've been working on other things, or if it's a
side effect of the improvements I made to typechecking for anonymous
objects, or something else, but I guess I'll take it!

Closes issue #543.

src/test/run-pass/anon-obj-overriding-reduced.rs

@@ -1,6 +1,4 @@
 //xfail-stage0
-//xfail-stage1
-//xfail-stage2
 
 // Reduced test case for issue #543.
 fn main() {

src/test/run-pass/anon-obj-overriding.rs

@@ -1,6 +1,5 @@
 //xfail-stage0
-//xfail-stage1
-//xfail-stage2
+
 use std;
 
 fn main() {
@@ -25,7 +24,6 @@ fn main() {
         with my_a
     };
 
-    // FIXME: raises a valgrind error (issue #543).
     assert (my_b.foo() == 3);
     assert (my_b.bar() == 3);
 }