Attach a copy of the record as JSON so we have an un-mangled copy.

def _attach_record_as_json(mfg_event, record):
  """Attach a copy of the record as JSON so we have an un-mangled copy."""
  attachment = mfg_event.attachment.add()
  attachment.name = TEST_RECORD_ATTACHMENT_NAME
  test_record_dict = htf_data.convert_to_base_types(record)
  attachment.value_binary = _convert_object_to_json(test_record_dict)
  attachment.type = test_runs_pb2.TEXT_UTF8