[KYUUBI #360] fix ut

Author: pan3793

kyuubi-common/src/main/scala/org/apache/kyuubi/util/ThriftUtils.scala

@@ -29,6 +29,8 @@ object ThriftUtils {
     }
   }
 
-  val EMPTY_ROW_SET = new TRowSet(0, new java.util.ArrayList[TRow](0))
+  def newEmptyRowSet: TRowSet = new TRowSet(0, new java.util.ArrayList[TRow](0))
+
+  val EMPTY_ROW_SET: TRowSet = newEmptyRowSet
 
 }

kyuubi-common/src/test/scala/org/apache/kyuubi/operation/NoopOperation.scala

@@ -76,7 +76,7 @@ class NoopOperation(typ: OperationType, session: Session, shouldFail: Boolean =
 
   override def getNextRowSet(order: FetchOrientation, rowSetSize: Int): TRowSet = {
     val col = TColumn.stringVal(new TStringColumn(Seq(typ.toString).asJava, ByteBuffer.allocate(0)))
-    val tRowSet = ThriftUtils.EMPTY_ROW_SET
+    val tRowSet = ThriftUtils.newEmptyRowSet
     tRowSet.addToColumns(col)
     tRowSet
   }