Remove duplicated CSS test

Exact same test is contained in WPT:
wpt/css/cssom/cssom-setProperty-shorthand.html

Change-Id: I930f6b9f1c43200392d7c9d120a5d9e58bd44b32
Reviewed-on: https://chromium-review.googlesource.com/1064065
Commit-Queue: Rob Buis <rbuis@igalia.com>
Reviewed-by: Chris Nardi <cnardi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559511}
2 files changed