[SPARK-14848][SQL] Compare as Set in DatasetSuite - Java encoder

## What changes were proposed in this pull request?
Change test to compare sets rather than sequence

## How was this patch tested?
Full test runs on little endian and big endian platforms

Author: Pete Robbins <robbinspg@gmail.com>

Closes #12610 from robbinspg/DatasetSuiteFix.

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

@@ -456,8 +456,8 @@ class DatasetSuite extends QueryTest with SharedSQLContext {
     implicit val kryoEncoder = Encoders.javaSerialization[JavaData]
     val ds = Seq(JavaData(1), JavaData(2)).toDS()
 
-    assert(ds.groupByKey(p => p).count().collect().toSeq ==
-      Seq((JavaData(1), 1L), (JavaData(2), 1L)))
+    assert(ds.groupByKey(p => p).count().collect().toSet ==
+      Set((JavaData(1), 1L), (JavaData(2), 1L)))
   }
 
   test("Java encoder self join") {