MINOR: Remove unused variable (apache#9303)

Reviewers: John Roesler <[email protected]>

Author: cadonna

streams/src/main/java/org/apache/kafka/streams/processor/internals/StreamThread.java

@@ -608,7 +608,6 @@ private void subscribeConsumer() {
      */
     // Visible for testing
     void runOnce() {
-        final ConsumerRecords<byte[], byte[]> records;
         final long startMs = time.milliseconds();
         now = startMs;