fix test

Author: cloud-fan

sql/catalyst/src/test/scala/org/apache/spark/sql/RowTest.scala

@@ -121,10 +121,6 @@ class RowTest extends FunSpec with Matchers {
       externalRow should be theSameInstanceAs externalRow.copy()
     }
 
-    it("copy should return same ref for internal rows") {
-      internalRow should be theSameInstanceAs internalRow.copy()
-    }
-
     it("toSeq should not expose internal state for external rows") {
       val modifiedValues = modifyValues(externalRow.toSeq)
       externalRow.toSeq should not equal modifiedValues