Update expectations on failing fast/filesystem/workers/file-writer* tests

TBR=dimich@chromium.org,kinuko@chromium.org
BUG=258949

Review URL: https://codereview.chromium.org/19575007

git-svn-id: svn://svn.chromium.org/blink/trunk@154613 bbb929c8-8fbe-4397-9dbb-9b2b20218538