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_nonce_table.h

@@ -13,7 +13,7 @@ namespace wvoec_ref {
 
 class NonceTable {
  public:
-  static const int kTableSize = 16;
+  static const int kTableSize = 4;
   NonceTable() {
     for (int i = 0; i < kTableSize; ++i) {
       state_[i] = kNTStateInvalid;
@@ -22,6 +22,8 @@ class NonceTable {
   ~NonceTable() {}
   void AddNonce(uint32_t nonce);
   bool CheckNonce(uint32_t nonce);
+  // Verify that the nonce is not the same as any in this table.
+  bool NonceCollision(uint32_t nonce) const;
   void Flush();
 
  private: