ci: Run unit tests with -race

I've attempted to enable 'go test -race', but there are many failures ([example](https://circleci.com/gh/hashicorp/consul/204265)). Data races could cause flaky tests, and may even cause issues in production.

I'm starting work on this in #8269. This issue is to track packages that have failures so that we can fix them incrementally.

* [x] agent/cache-types - #9160
* [x] agent/local
* [x] agent/xds - #9461
* [x] connect - #9160
* [x] connect/proxy - #9160
* [ ] agent
* [x] agent/consul - #10341
* [x] snapshot
* [x] command/{acl,etc...} - #10341
* [ ] (other packages not yet listed)

Related issues:
* https://github.com/hashicorp/memberlist/issues/134#issuecomment-749787468 looks to still be an issue
* https://github.com/hashicorp/raft-autopilot/issues/3
* https://github.com/hashicorp/consul/issues/9457
* https://github.com/hashicorp/serf/issues/622
* https://github.com/hashicorp/consul/issues/9458