message: Avoid the primitive set in aead_config_test.
  We can simply create an AEAD to prove that the wrapper is registered; this is way easier and doesn't use the primitive set API (which is really best avoided).
diff: #include "tink/util/status.h"
  #include "tink/util/statusor.h"
  #include "tink/util/test_matchers.h"
  -#include "tink/util/test_util.h"
  #include "proto/tink.pb.h"
  namespace crypto {
  namespace tink {
  namespace {
  -using ::crypto::tink::test::DummyAead;
  using ::crypto::tink::test::IsOk;
  using ::crypto::tink::test::StatusIs;
  -using ::google::crypto::tink::KeysetInfo;
  -using ::google::crypto::tink::KeyStatusType;
  +using ::crypto::tink::util::StatusOr;
  using ::google::crypto::tink::KeyTemplate;
  -using ::google::crypto::tink::OutputPrefixType;
  using ::testing::Eq;
  +using ::testing::IsNull;
  using ::testing::Not;
  using ::testing::Test;
  @@ -80,30 +77,12 @@ TEST_F(AeadConfigTest, WrappersRegistered) {
  ASSERT_THAT(AeadConfig::Register(), IsOk());
  - KeysetInfo::KeyInfo key_info;
  - key_info.set_status(KeyStatusType::ENABLED);
  - key_info.set_key_id(1234);
  - key_info.set_output_prefix_type(OutputPrefixType::RAW);
  - auto primitive_set = absl::make_unique<PrimitiveSet<Aead>>();
  - ASSERT_THAT(primitive_set->set_primary(*primitive_set->AddPrimitive(
  - absl::make_unique<DummyAead>("dummy"), key_info)),
  - IsOk());
  -
  - util::StatusOr<std::unique_ptr<Aead>> primitive_result =
  - Registry::Wrap(std::move(primitive_set));
  -
  - ASSERT_THAT(primitive_result, IsOk());
  - util::StatusOr<std::string> encryption_result =
  - (*primitive_result)->Encrypt("secret", "");
  - ASSERT_THAT(encryption_result, IsOk());
  -
  - util::StatusOr<std::string> decryption_result =
  - DummyAead("dummy").Decrypt(*encryption_result, "");
  - ASSERT_THAT(decryption_result, IsOk());
  - EXPECT_THAT(*decryption_result, Eq("secret"));
  -
  - decryption_result = DummyAead("dummy").Decrypt(*encryption_result, "wrong");
  - EXPECT_THAT(decryption_result, Not(IsOk()));
  + StatusOr<std::unique_ptr<KeysetHandle>> keyset_handle =
  + KeysetHandle::GenerateNew(AeadKeyTemplates::Aes128Gcm());
  + ASSERT_THAT(keyset_handle.status(), IsOk());
  + StatusOr<std::unique_ptr<Aead>> aead = (*keyset_handle)->GetPrimitive<Aead>();
  + ASSERT_THAT(aead.status(), IsOk());
  + ASSERT_THAT(*aead, Not(IsNull()));
  }
  // FIPS-only mode tests
  