Remove a "Timeout" label for a layout test

The chromium flakiness dashboard shows this test is not timing out:
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=canvas-partial-invalidation-zoomed.html

TBR=junov@chromium.org
BUG=440452

Review-Url: https://codereview.chromium.org/2164763004
Cr-Commit-Position: refs/heads/master@{#406688}
1 file changed