Now that libwebp is updated to 0.4.0, mark some tests as NeedsRebaseline

BUG=331619
R=jzern@chromium.org

Review URL: https://codereview.chromium.org/137043004

git-svn-id: svn://svn.chromium.org/blink/trunk@164995 bbb929c8-8fbe-4397-9dbb-9b2b20218538