Remove unnecessary copy() and test cases.

Author: viirya

sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala

@@ -225,7 +225,7 @@ case class TakeOrderedAndProject(
   private def collectData(): Array[InternalRow] = {
     val data = child.execute().map(_.copy()).takeOrdered(limit)(ord)
     if (projection.isDefined) {
-      projection.map(p => data.map(p(_).copy().asInstanceOf[InternalRow])).get
+      projection.map(p => data.map(p(_).asInstanceOf[InternalRow])).get
     } else {
       data
     }

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -571,12 +571,6 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
       mapData.collect().take(1).map(Row.fromTuple).toSeq)
   }
 
-  test("sort and limit") {
-    checkAnswer(
-      sql("SELECT * FROM arrayData ORDER BY data[0] ASC LIMIT 1"),
-      arrayData.collect().sortBy(_.data(0)).map(Row.fromTuple).take(1).toSeq)
-  }
-
   test("CTE feature") {
     checkAnswer(
       sql("with q1 as (select * from testData limit 10) select * from q1"),