[SPARK-19805][TEST] Log the row type when query result dose not match

## What changes were proposed in this pull request?

improve the log message when query result does not match.

before pr:

```
== Results ==
!== Correct Answer - 3 ==   == Spark Answer - 3 ==
 [1]                        [1]
 [2]                        [2]
 [3]                        [3]

```

after pr:

~~== Results ==
!== Correct Answer - 3 ==   == Spark Answer - 3 ==
!RowType[string]            RowType[integer]
 [1]                        [1]
 [2]                        [2]
 [3]                        [3]~~

```
== Results ==
!== Correct Answer - 3 ==   == Spark Answer - 3 ==
!struct<value:string>       struct<value:int>
 [1]                        [1]
 [2]                        [2]
 [3]                        [3]
```

## How was this patch tested?

Jenkins

Author: uncleGen <hustyugm@gmail.com>

Closes #17145 from uncleGen/improve-test-result.

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

@@ -312,13 +312,23 @@ object QueryTest {
       sparkAnswer: Seq[Row],
       isSorted: Boolean = false): Option[String] = {
     if (prepareAnswer(expectedAnswer, isSorted) != prepareAnswer(sparkAnswer, isSorted)) {
+      val getRowType: Option[Row] => String = row =>
+        row.map(row =>
+            if (row.schema == null) {
+              "struct<>"
+            } else {
+                s"${row.schema.catalogString}"
+            }).getOrElse("struct<>")
+
       val errorMessage =
         s"""
          |== Results ==
          |${sideBySide(
         s"== Correct Answer - ${expectedAnswer.size} ==" +:
+         getRowType(expectedAnswer.headOption) +:
          prepareAnswer(expectedAnswer, isSorted).map(_.toString()),
         s"== Spark Answer - ${sparkAnswer.size} ==" +:
+         getRowType(sparkAnswer.headOption) +:
          prepareAnswer(sparkAnswer, isSorted).map(_.toString())).mkString("\n")}
         """.stripMargin
       return Some(errorMessage)