fix the test

Author: TingDaoK

tests/s3_checksum_stream_test.c

@@ -143,6 +143,7 @@ static int compare_chunk_stream(
     struct aws_byte_buf read_buf;
     aws_byte_buf_init(&read_buf, allocator, buffer_size);
     for (size_t i = 0; i < AWS_ARRAY_SIZE(s_checksum_algo_priority_list); i++) {
+        AWS_ZERO_STRUCT(streamed_encoded_checksum);
         enum aws_s3_checksum_algorithm algorithm = s_checksum_algo_priority_list[i];
         aws_base64_compute_encoded_len(aws_get_digest_size_from_checksum_algorithm(algorithm), &encoded_len);
         size_t total_len =