Update unit tests for v15.2

Merge from Widevine repo of http://go/wvgerrit/77609

For v15.2 we require that nonces not collide across sessions and there are
restrictions placed on the mac key's IV in LoadKeys.

Test: ran unit tests on reference code

Bug: 131325434
Bug: 131326334

Change-Id: I1bb01c30d8c15d66d762c28b57d7700c44daa835

libwvdrmengine/oemcrypto/ref/src/oemcrypto_engine_ref.h

@@ -91,6 +91,10 @@ class CryptoEngine {
 
   time_t RollbackCorrectedOfflineTime();
 
+  // Verify that this nonce does not collide with another nonce in any session's
+  // nonce table.
+  virtual bool NonceCollision(uint32_t nonce);
+
   // Returns the HDCP version currently in use.
   virtual OEMCrypto_HDCP_Capability config_current_hdcp_capability();