Unskip more tests that are no longer flaky

Follow up to https://codereview.chromium.org/2686693002, these tests should
no longer be flaky.

TBR=eae@chromium.org

BUG=663855

Review-Url: https://codereview.chromium.org/2704023002
Cr-Commit-Position: refs/heads/master@{#451486}
1 file changed