Unit Tests for Security Patch Level

Merge of widevine change http://go/wvgerrit/16249

This CL adds unit tests and reference code for the security patch
level, which is a new feature in OEMCrypto v11.  This CL also adjusts
the dynamic and static adapters to still run with devices that have a
v10 OEMCrypto.

The level 3 haystack code will be updated in a future CL.

bug: 26188985

Change-Id: I518ef46b4098cf3718fe0c0390bfb6825db4fb6b

libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.h

@@ -259,6 +259,7 @@ class CryptoEngine {
   bool supports_keybox();
   bool is_anti_rollback_hw_present();
   const char* security_level();
+  uint8_t security_patch_level();
 
  private:
   bool LoadPkcs8RsaKey(const uint8_t* buffer, size_t length);