Remove timeout expectation for LayoutTest virtual/web-animations-css/animations/dynamic-stylesheet-loading.html

This test was fixed by https://codereview.chromium.org/26491013

R=dstockwell

Review URL: https://codereview.chromium.org/33843004

git-svn-id: svn://svn.chromium.org/blink/trunk@160301 bbb929c8-8fbe-4397-9dbb-9b2b20218538