fix: TestRecordBatchDecoding failing sporadically
fix: TestRecordBatchDecoding failing sporadically

uses copy of test data to ensure independence between encoding and decoding tests.

Signed-off-by: kwall <82661567142926be395d42451b0008b62207b650@apache.org>

DataDog/sarama,Shopify/sarama,Shopify/sarama,DataDog/sarama