Fix layout test expectation for W3C web-platform-tests
Fix layout test expectation for W3C web-platform-tests

In https://codereview.chromium.org/1242303002/ there are some missing
updates for WPT shadow-dom tests.
This fixes by updating the expectation.

BUG=484953,505364

Review URL: https://codereview.chromium.org/1245903002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@199206 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk