Fix Go code intelligence
Created by: nicksnyder
In OSS, we run Go code intelligence in a docker container. Inside the container 127.0.0.1 does not map to the localhost of the container. host.docker.internal does though (on Docker for Mac and Windows, but not Linux). It doesn't seem like there is a universal solution that works for both Mac and Linux (https://dev.to/bufferings/access-host-from-a-docker-container-4099).
In enterprise, we run Go code intelligence in process per https://github.com/sourcegraph/sourcegraph/issues/177#issuecomment-426144313 so it does need to be 127.0.0.1 there.