[ Merge of http://go/wvgerrit/174470 ] There are two sets of changes * Mocking CryptoSession so that OEMCrypto API version can be queried * Creating a PolicyEngineTestV16 so that API version expectations can be set and V18 can be accommodated. Bug: 278751387 Test: policy_engine_unittest Change-Id: Ied664ce87e22f697b6a45d3c573e22273e65e37f