Support invalidation sets for :-webkit-any selectors.

Traverse the selectorList() like we do for :host to find features for
invalidation sets. Relevance for 351613 is that we need to support this in
order to implement efficient invalidation sets for :hover with
childrenAffectedByHover due to UA stylesheet rules.

R=esprehn
BUG=356125,351613

Review URL: https://codereview.chromium.org/210973004

git-svn-id: svn://svn.chromium.org/blink/trunk@170212 bbb929c8-8fbe-4397-9dbb-9b2b20218538