When I "PUT" an object using a pre-signed by localstack S3 URL, the localstack responds with "Content Length: 233" and `<PutObjectResponse>...</PutObjectResponse>` XML in the body. 

When I run the same code against AWS S3, the content length is 0 and response body blank. Would be great if localstack matched the AWS S3 response.

Running the latest 0.9.3 localstack docker image.
key_by_path = 'key-by-hostname'
        
        queue_url = self.sqs_client.create_queue(QueueName=TEST_QUEUE_FOR_BUCKET_WITH_NOTIFICATION)['QueueUrl']
        queue_attributes = self.sqs_client.get_queue_attributes(QueueUrl=queue_url, AttributeNames=['QueueArn'])
        
        self.s3_client.create_bucket(Bucket=TEST_BUCKET_WITH_NOTIFICATION)
        self.s3_client.put_bucket_notification_configuration(Bucket=TEST_BUCKET_WITH_NOTIFICATION,
            NotificationConfiguration={'QueueConfigurations': [
                {'QueueArn': queue_attributes['Attributes']['QueueArn'], 'Events': ['s3:ObjectCreated:*']}]})
        
        self._perform_multipart_upload(bucket=TEST_BUCKET_WITH_NOTIFICATION, key=key_by_path, zip=True)
        queue_attributes = self.sqs_client.get_queue_attributes(
            QueueUrl=queue_url, AttributeNames=['ApproximateNumberOfMessages'])
        message_count = queue_attributes['Attributes']['ApproximateNumberOfMessages']
        
        self.assertEqual(message_count, '1')
        
        self.sqs_client.delete_queue(QueueUrl=queue_url)
        self.s3_client.delete_objects(Bucket=TEST_BUCKET_WITH_NOTIFICATION,
                                 Delete={'Objects': [{'Key': key_by_path}]})
        self.s3_client.delete_bucket(Bucket=TEST_BUCKET_WITH_NOTIFICATION)
    def test_s3_get_response_default_content_type(self):