More expectation updates for bug 248938, since it seems to be a neverending
source of bot flakiness.

BUG=248938
TEST=none
TBR=apavlov

Review URL: https://codereview.chromium.org/180723014

git-svn-id: svn://svn.chromium.org/blink/trunk@168068 bbb929c8-8fbe-4397-9dbb-9b2b20218538