Expand flakiness of inspector/styles/styles-new-API.html.

It's flaking on Win.

TBR=pfeldman
BUG=273119

Review URL: https://codereview.chromium.org/49463004

git-svn-id: svn://svn.chromium.org/blink/trunk@160744 bbb929c8-8fbe-4397-9dbb-9b2b20218538