Do not set Content-MD5 in S3. (#5226)

[SC-52300](https://app.shortcut.com/tiledb-inc/story/52300/do-not-set-content-md5-in-s3)

This PR removes setting the `Content-MD5` header on S3 uploads. There
are multiple reasons for this:

* The header is [not supported on directory
buckets](https://docs.aws.amazon.com/AmazonS3/latest/userguide/s3-express-differences.html#s3-express-differences-unsupported-features)
used by S3 Express One Zone.
* Computing the MD5 hash of the data immediately before uploading them
has a performance overhead and does not provide additional security.
* We don't do a similar thing in the other cloud VFSes.

Validated by:
* Creating, writing, consolidating and vacuuming an array on a directory
bucket.
* Running `quickstart_dense_cpp` on a Google Cloud Storage bucket using
the S3 compatibility API.

---
TYPE: BUG
DESC: Fix incompatibilities with S3 Express One Zone, by stopping
setting `Content-MD5` on all S3 uploads.

Co-authored-by: KiterLuc <[email protected]>

tiledb/sm/filesystem/s3.cc

@@ -1786,12 +1786,6 @@ void S3::write_direct(const URI& uri, const void* buffer, uint64_t length) {
   put_object_request.SetBody(stream);
   put_object_request.SetContentLength(length);
 
-  // we only want to hash once, and must do it after setting the body
-  auto md5_hash =
-      Aws::Utils::HashingUtils::CalculateMD5(*put_object_request.GetBody());
-
-  put_object_request.SetContentMD5(
-      Aws::Utils::HashingUtils::Base64Encode(md5_hash));
   put_object_request.SetContentType("application/octet-stream");
   put_object_request.SetBucket(aws_uri.GetAuthority());
   put_object_request.SetKey(aws_uri.GetPath());
@@ -1815,16 +1809,6 @@ void S3::write_direct(const URI& uri, const void* buffer, uint64_t length) {
         outcome_error_message(put_object_outcome));
   }
 
-  // verify the MD5 hash of the result
-  // note the etag is hex-encoded not base64
-  Aws::StringStream md5_hex;
-  md5_hex << "\"" << Aws::Utils::HashingUtils::HexEncode(md5_hash) << "\"";
-  if (md5_hex.str() != put_object_outcome.GetResult().GetETag()) {
-    throw S3Exception(
-        "Object uploaded successfully, but MD5 hash does "
-        "not match result from server!' ");
-  }
-
   throw_if_not_ok(wait_for_object_to_propagate(
       put_object_request.GetBucket(), put_object_request.GetKey()));
 }
@@ -1974,8 +1958,6 @@ S3::MakeUploadPartCtx S3::make_upload_part_req(
   upload_part_request.SetPartNumber(upload_part_num);
   upload_part_request.SetUploadId(upload_id);
   upload_part_request.SetBody(stream);
-  upload_part_request.SetContentMD5(Aws::Utils::HashingUtils::Base64Encode(
-      Aws::Utils::HashingUtils::CalculateMD5(*stream)));
   upload_part_request.SetContentLength(length);
   if (request_payer_ != Aws::S3::Model::RequestPayer::NOT_SET)
     upload_part_request.SetRequestPayer(request_payer_);