Cleanup test setup when watching for balance in production

[da-kami]

With #216 we added a loop to make sure the wallet has caught up with the balance in the test setup.

Once we implement watching for deposit #196 we should remove the code added by #216 and ensure we use the production code for waiting for the balance to catch up.

[thomaseizinger]

This seems to be no longer valid.

The premise was that we might be able to re-use the 'watch for deposit' functionality but that turned out not to be true, hence closing this.