Initialize gtest correctly

test/cpp/client/channel_arguments_test.cc

@@ -119,6 +119,6 @@ TEST_F(ChannelArgumentsTest, SetString) {
 }  // namespace grpc
 
 int main(int argc, char** argv) {
-
+  ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }

test/cpp/client/credentials_test.cc

@@ -65,7 +65,7 @@ TEST_F(CredentialsTest, InvalidServiceAccountCreds) {
 }  // namespace grpc
 
 int main(int argc, char **argv) {
-
+  ::testing::InitGoogleTest(&argc, argv);
   grpc_init();
   int ret = RUN_ALL_TESTS();
   grpc_shutdown();