CE backport for "Use gitlab-elasticsearch-indexer in tests"
What does this MR do?
Ports some changes to TestEnv
in https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/12680 to CE.
We're rescuing the gitlab-elasticsearch-indexer
component from being cleaned by adding it to a whitelist. I feel like we should stop putting components into tmp/tests
so this doesn't have to be a thing any more. They could go into tmp/components
instead, but perhaps that's best left for another time.