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.cpp

@@ -58,6 +58,13 @@ bool NonceTable::CheckNonce(uint32_t nonce) {
   return false;
 }
 
+bool NonceTable::NonceCollision(uint32_t nonce) const {
+  for (int i = 0; i < kTableSize; ++i) {
+    if (nonce == nonces_[i]) return true;
+  }
+  return false;
+}
+
 void NonceTable::Flush() {
   for (int i = 0; i < kTableSize; ++i) {
     if (kNTStateFlushPending == state_[i]) {