We are using go modules and they don't behave when inside of the GOROOT:
```
PS C:\Go\src\gitlab.com\gitlab-org\gitlab-runner> go test -v gitlab.com/gitlab-org/gitlab-runner/helpers/process
go: inconsistent vendoring in C:\Go\src\gitlab.com\gitlab-org\gitlab-runner:
        go.mod requires gitlab.com/gitlab-org/gitlab-runner  but vendor/modules.txt does not include it.
        run 'go mod tidy; go mod vendor' to sync
```

The Runner source code doesn't have to be inside of the $GOROOT/$GOPATH
anymore since it's using modules.