Make TestResponse properly inherit Response.

There are a number of problems doing things like .json() if you don't
inherit the correct parameters.

Change-Id: I0dfc8ab6486090fbcd28792c18deae67e4769d53
Merge "Make TestResponse properly inherit Response."
Updated from global requirements

Change-Id: If137689e5b9008c51cea16d41e648f0df490a247