Gardening: http/tests/local/formdata/send-form-data.html times out on Win

BUG=371716
TBR=ojan

Review URL: https://codereview.chromium.org/278813002

git-svn-id: svn://svn.chromium.org/blink/trunk@173735 bbb929c8-8fbe-4397-9dbb-9b2b20218538