Fixes

Author: JoshRosen

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

@@ -306,6 +306,8 @@ case class UnsafeExternalSort(
   override def output: Seq[Attribute] = child.output
 
   override def outputOrdering: Seq[SortOrder] = sortOrder
+
+  override def outputsUnsafeRows: Boolean = true
 }
 
 @DeveloperApi

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

@@ -104,4 +104,4 @@ private[sql] object EnsureRowFormats extends Rule[SparkPlan] {
         operator
       }
   }
-}
+}