servo: Merge #16456 - Use the bloom filter for child selectors (from bholley:bloom_children); r=emilio

This speeds up bloom-basic-ref.html by 4x on my machine.

Source-Repo: https://github.com/servo/servo
Source-Revision: b37f4952bd6f2c0177ad462e3445ac79dac19ecb

servo/components/selectors/matching.rs

@@ -122,6 +122,7 @@ fn may_match<E>(mut selector: &ComplexSelector<E::Impl>,
     loop {
          match selector.next {
              None => break,
+             Some((ref cs, Combinator::Child)) |
              Some((ref cs, Combinator::Descendant)) => selector = &**cs,
              Some((ref cs, _)) => {
                  selector = &**cs;