Stability testing for visual regression tests

[liza-mae]

We need a way to run visual tests multiple times to test for stability in PRs and also in our flaky test suite runner. In visual testing, when we have added new tests we need a way to have a baseline to test against before it is merged into master, I have a way I do this but we should come up with a standard and put it into our workflows. The percy project and/or the percy branch and target branch can be used.

cc: @spalger @brianseeders

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[tylersmalley]

Closing this as we no longer run visual tests.