Re-enable Bazel Federation in downstream (#1043)
Re-enable Bazel Federation in downstream (#1043)

Bazel Federation is now green with Bazel@HEAD
https://buildkite.com/bazel/bazel-at-head-plus-disabled/builds/700
bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration