Add broader style-invalidation regression coverage for selector shapes
that are easy to mis-model when invalidation data is flattened into
feature sets. Cover selector-list alternatives, nested pseudo-class
arguments, pseudo-element arguments, nth-child selector lists,
quirks-mode class matching, mixed-case ancestor filters, duplicate
invalidation rule merging, and concrete :has() feature filtering.
Keep the expectations on the unoptimized baseline so follow-up
optimization commits can show the counter progressions separately.
These tests dump the normal invalidation counters instead of asserting
specific counter values in script.
c9cac66677