[SPARK-21843] testNameNote should be "(minNumPostShufflePartitions: 5)"

Signed-off-by: iamhumanbeing <iamhumanbeinggmail.com>

## What changes were proposed in this pull request?

testNameNote = "(minNumPostShufflePartitions: 3) is not correct.
it should be "(minNumPostShufflePartitions: " + numPartitions + ")" in ExchangeCoordinatorSuite

## How was this patch tested?

unit tests

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: iamhumanbeing <[email protected]>

Closes apache#19058 from iamhumanbeing/testnote.

Author: iamhumanbeing

sql/core/src/test/scala/org/apache/spark/sql/execution/ExchangeCoordinatorSuite.scala

@@ -280,7 +280,7 @@ class ExchangeCoordinatorSuite extends SparkFunSuite with BeforeAndAfterAll {
 
   Seq(Some(5), None).foreach { minNumPostShufflePartitions =>
     val testNameNote = minNumPostShufflePartitions match {
-      case Some(numPartitions) => "(minNumPostShufflePartitions: 3)"
+      case Some(numPartitions) => "(minNumPostShufflePartitions: " + numPartitions + ")"
       case None => ""
     }