tests: Check the the ecdsa_nid is the same.

tests/unittests/torture_pki.c

@@ -789,9 +789,11 @@ static void torture_pki_ecdsa_duplicate_then_demote(void **state)
 
     privkey_dup = ssh_key_dup(privkey);
     assert_true(privkey_dup != NULL);
+    assert_int_equal(privkey->ecdsa_nid, privkey_dup->ecdsa_nid);
 
     rc = ssh_pki_export_privkey_to_pubkey(privkey_dup, &pubkey);
     assert_true(rc == 0);
+    assert_int_equal(pubkey->ecdsa_nid, privkey->ecdsa_nid);
 
     ssh_key_free(pubkey);
     ssh_key_free(privkey);