Bug: chalice deploy not discovering correct permissions when client may be stubbed

I've implemented a simillar test pattern to the one suggested [here](https://aws.amazon.com/blogs/developer/introducing-the-new-test-client-for-aws-chalice/) under the heading "Testing with the AWS SDK for Python", however this prevents chalice deploy from discovering the correct permissions. Similar issue to https://github.com/aws/chalice/issues/692, but different code example (see example code from linked aws docs).

Start with the AWS testing example linked in the issue and compare its stubbed-client behavior with the related issue #692. Trace how chalice deploy discovers permissions in this setup; done means deployment identifies the correct permissions when the client is stubbed.

Written by the indexing model from the issue text.