Re-enable `e2e` tests

#9 disabled the end-to-end unit tests to make it easier to piecemeal the conversion and hardening of the functionality.

This is to re-enable the original end-to-end tests.

We should switch to using gitlab.arm.com projects for cloning as much as possible. We may even want to create a mock project with some submodules in it to test the submodule setup to remove the load on GitHub. We could create them under bazel/test/fixture if needed.