Do not fall back to L3 if L1 has test keybox

ag/26105061 accidentally reverted some of these changes so I am pushing
up another patch to add them back in.

[ Merged of go/wvgerrit/186370 ]

CDM by default allows test keybox from device side.

Bug: 299987160
Bug: 301669353
Change-Id: I6acf93c78f76a13f2c4539aabfd0262670b54c48

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -332,12 +332,6 @@ class CdmEngine {
     return CryptoSession::SetDebugIgnoreKeyboxCount(count);
   }
 
-  // This tells the OEMCrypto adapter to allow the device to continue with a
-  // test keybox. Otherwise, the keybox is reported as invalid.
-  static CdmResponseType SetAllowTestKeybox(bool allow) {
-    return CryptoSession::SetAllowTestKeybox(allow);
-  }
-
   static CdmResponseType ParseDecryptHashString(const std::string& hash_string,
                                                 CdmSessionId* id,
                                                 uint32_t* frame_number,