remove unused code

Author: HeartSaVioR

sql/core/src/main/scala/org/apache/spark/sql/execution/python/PythonArrowInput.scala

@@ -26,7 +26,6 @@ import org.apache.spark.{SparkEnv, TaskContext}
 import org.apache.spark.api.python.{BasePythonRunner, PythonRDD}
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.execution.arrow.ArrowWriter
-import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types.StructType
 import org.apache.spark.sql.util.ArrowUtils
 import org.apache.spark.util.Utils

sql/core/src/main/scala/org/apache/spark/sql/execution/python/PythonArrowOutput.scala

@@ -41,10 +41,6 @@ private[python] trait PythonArrowOutput[OUT <: AnyRef] { self: BasePythonRunner[
 
   protected def deserializeColumnarBatch(batch: ColumnarBatch, schema: StructType): OUT
 
-  protected def handleStateUpdate(stream: DataInputStream): Unit = {
-    new IllegalStateException("Should not reach here!")
-  }
-
   protected def newReaderIterator(
       stream: DataInputStream,
       writerThread: WriterThread,