stylo: Fix restyle hints check.

It's clearly wrong to use intersects() there, since the coming check may be a
bigger hint.

MozReview-Commit-ID: 1YZ8OD0ajSz
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>

components/style/restyle_hints.rs

@@ -684,7 +684,7 @@ impl DependencySet {
             debug_assert!((!state_changes.is_empty() && !dep.sensitivities.states.is_empty()) ||
                           (attrs_changed && dep.sensitivities.attrs),
                           "Testing a known ineffective dependency?");
-            if (attrs_changed || state_changes.intersects(dep.sensitivities.states)) && !hint.intersects(dep.hint) {
+            if (attrs_changed || state_changes.intersects(dep.sensitivities.states)) && !hint.contains(dep.hint) {
                 // We can ignore the selector flags, since they would have already been set during
                 // original matching for any element that might change its matching behavior here.
                 let matched_then =