Merge from Widevine repo of http://go/wvgerrit/100964
The previous nonce-free test used the same session to generate the
request as to load the license. However, it is a realistic use case to
have a new session used for loading the license.
The use case relates to a pre-loaded, shared license.
Test: Ran unit tests on taimen and on v16 ref implementation
Bug: 156853321
Change-Id: Ibc07744a16edcd3952d88d73660a75d0c3e8eeb8
a615671f48