Adding tests to verify `EVP_PKEY_from_keystore2` API [Keystore2-engine].

1. Generate RSA key and grant it to a user. In user context load the
   key using `EVP_PKEY_from_keystore` and perform sign and verify
   opeearions.
   [keystore2_perofrm_crypto_op_using_keystore2_engine_rsa_key_success]

2. Generate EC key and grant it to a user. In user context load the
   key using `EVP_PKEY_from_keystore` and perform sign and verify
   operations.
   [keystore2_perofrm_crypto_op_using_keystore2_engine_ec_key_success]

3. Generate RSA key and grant it to a user. Re-encode the certificate
   as PEM and update the certificate using `updateSubcomponents`.
   In user context load the key using `EVP_PKEY_from_keystore` and
   perform sign and verify operations.

Bug: 201343811
Test: atest keystore2_client_tests
Change-Id: I7dafd598f4198e11103cd11695b2f67636f24755
diff --git a/keystore2/test_utils/key_generations.rs b/keystore2/test_utils/key_generations.rs
index e4c4968..3422ce8 100644
--- a/keystore2/test_utils/key_generations.rs
+++ b/keystore2/test_utils/key_generations.rs
@@ -299,6 +299,9 @@
     /// Error code to indicate error in ASN.1 DER-encoded data creation.
     #[error("Failed to create and encode ASN.1 data.")]
     DerEncodeFailed,
+    /// Error code to indicate error while using keystore-engine API.
+    #[error("Failed to perform crypto op using keystore-engine APIs.")]
+    Keystore2EngineOpFailed,
 }
 
 /// Keystore2 error mapping.