ServiceWorker: Remove outdated expectations from FlakyTests


BUG=408048
TBR=horo@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/586453006

git-svn-id: svn://svn.chromium.org/blink/trunk@182296 bbb929c8-8fbe-4397-9dbb-9b2b20218538