Import external/wpt/css/css-lists

Most of the tests in external/wpt/css/css-lists were contributed by
Chrome, but we skip the directory on import. There is one new reftest
that passes, and two visual tests that should not be run. Remove the
line skipping this directory from W3CImportExpectations.

Change-Id: Icfe1d7e7cca98a79c1eb8c532ca169367ba460b4
Reviewed-on: https://chromium-review.googlesource.com/959781Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Commit-Queue: Philip Jägenstedt <foolip@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542938}

third_party/WebKit/LayoutTests/W3CImportExpectations

@@ -86,7 +86,6 @@ external/wpt/css/css-counter-styles [ Skip ]
 external/wpt/css/css-display/run-in [ Skip ]
 external/wpt/css/css-exclusions [ Skip ]
 external/wpt/css/css-gcpm [ Skip ]
-external/wpt/css/css-lists [ Skip ]
 external/wpt/css/css-masking [ Skip ]
 external/wpt/css/css-page [ Skip ]
 external/wpt/css/css-regions [ Skip ]