Merge pull request rust-lang#4315 from RalfJung/test-cleanup

remove stray stderr file

Author: RalfJung

src/tools/miri/tests/fail/weak_memory/racing_mixed_size.stderr

@@ -12,7 +12,6 @@ fn main() {
     mut_raw_mut();
     partially_invalidate_mut();
     drop_after_sharing();
-    // direct_mut_to_const_raw();
     two_raw();
     shr_and_raw();
     disjoint_mutable_subborrows();