[LayoutNG] Add 2nd flaky results to FlagExpectations for LayoutNG

This patch adds another flaky results from 5-6 iterations of running
tests.

I will run a few more iterations and see how it stabilizes.

BUG=591099

Review-Url: https://codereview.chromium.org/2840753003
Cr-Commit-Position: refs/heads/master@{#467256}
1 file changed