cluster-api-provider-aws: Unit tests should not need to call reconcile()

In the unit tests that use testenv, instance creation should trigger reconciliation automatically and hence we don’t need to trigger reconcile().

For this, we need to add the reconciler by calling SetupWithManager() similar to: https://github.com/kubernetes-sigs/cluster-api-provider-aws/blob/76ea0c9445caa2ecbdcf97a24dcaf0433a6f8139/exp/instancestate/awsinstancestate_controller_test.go#L87

/kind cleanup /help /good-first-issue