Gardening: remove wrong expectations for Win XP

delete LayoutTests/platform/win-xp/svg/filters/feMerge-wrong-input-expected.txt

BUG=
TBR= jianli@chromium.org

Review URL: https://codereview.chromium.org/567983002

git-svn-id: svn://svn.chromium.org/blink/trunk@181888 bbb929c8-8fbe-4397-9dbb-9b2b20218538