Pick widevine oemcrypto-v18 change

No-Typo-Check: From a third party header file
Bug: 260918793
Test: unit tests
Test: atp v2/widevine-eng/drm_compliance
Change-Id: I36effd6a10a99bdb2399ab1f4a0fad026d607c70

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_generate_signature.cc

@@ -15,7 +15,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   }
 
   OEMCrypto_Initialize();
-  session_helper.EnsureTestKeys();
+  OEMCrypto_EnterTestMode();
+  session_helper.EnsureTestROT();
 
   Session s;
   s.open();