Limit the number of archived results in Layout Tests.

There has to be a limit on the number of results that can be archived because they take up considerable amount of disk space.

Review URL: https://codereview.chromium.org/452493002

git-svn-id: svn://svn.chromium.org/blink/trunk@179792 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Removal of the no longer flaky test from the list

webgl-remote-read-remote-image-allowed-with-credentials.html test is no 
longer flaky for DEBUG Linux as per the flakiness dashboard.

http://test-results.appspot.com/dashboards/flakiness_dashboard.html

Review URL: https://codereview.chromium.org/440343002

git-svn-id: svn://svn.chromium.org/blink/trunk@179793 bbb929c8-8fbe-4397-9dbb-9b2b20218538