I will ask Google about this, but I expect the response to read something like, “We are continuously testing ways to improve the search experience with our search ads.”
Postscript: Here is the official Google statement on this test:
As part of our ongoing commitment to help users find the information they’re looking for online, we are testing a feature in which links to various pages of an advertiser’s website may appear within the text ads on Google.com. Presenting multiple landing page options is intended to make specific website information such as gift registries, special deals, store locators and the like more easily accessible to users. It also offers brand marketers a new way to quickly engage potential customers. This feature is currently in a limited beta with a small number of advertisers.