Permissions: Fix Auth CTS tests to reflect changes.

Added a new CtsUnaffiliatedAccountAuthenticators support package signed
with different keys to allow us to test expected failures when trying to
use AccountManager methods that require signature matching.

Also replaced the permissions/src/.../AccountManagerTest with similar
tests in AccountManagerUnaffiliatedAuthenticatorTests that will do the
right thing.

There aren't any tests that check whether an unaffiliated client with
the GET_ACCOUNTS permission can get accounts. But that isn't a
regression.  accounts/src/.../AccountManagerTests tests that matching
signatures get the correct data. While the unaffiliated tests make sure
that those that don't have the relevant permissions don't get data.

Also added some infrastructure (TestAuthenticator implementation) for future use.

Bug: 22330923
Change-Id: Ide02af19c41191079138c22071e0055027498c7b
38 files changed