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_session.h

@@ -173,6 +173,10 @@ class SessionContext {
 
   void AddNonce(uint32_t nonce);
   bool CheckNonce(uint32_t nonce);
+  // Verify that the nonce does not match any in this session's nonce table.
+  bool NonceCollision(uint32_t nonce) const {
+    return nonce_table_.NonceCollision(nonce);
+  }
   void FlushNonces();
 
   virtual OEMCryptoResult CreateNewUsageEntry(uint32_t* usage_entry_number);