Merge from Widevine repo of http://go/wvgerrit/96508
This adds a unit test for to verify that a preloaded license may be
loaded into OEMCrypto. A preloaded license is a license that does not
have a nonce, and for which there is no license request. This is used
in CAS and ATSC.
I also updated the test version string to
OEMCrypto unit tests for API 16.2. Tests last updated 2020-03-27
Bug: 144105097
Test: ran oemcrypto unit tests on taimen and with v16 modmock.
Change-Id: I6a4926917f36a084d15defa7b908d067612c4dcf
ca404aae6f