[SS][MINOR] Fix flaky test in DatastreamReaderWriterSuite. temp check…

…point dir should be deleted

## What changes were proposed in this pull request?

Stopping query while it is being initialized can throw interrupt exception, in which case temporary checkpoint directories will not be deleted, and the test will fail.

Author: Tathagata Das <tathagata.das1565@gmail.com>

Closes apache#18442 from tdas/DatastreamReaderWriterSuite-fix.

(cherry picked from commit 60043f2)
Signed-off-by: Tathagata Das <tathagata.das1565@gmail.com>

sql/core/src/test/scala/org/apache/spark/sql/streaming/test/DataStreamReaderWriterSuite.scala

@@ -641,6 +641,7 @@ class DataStreamReaderWriterSuite extends StreamTest with BeforeAndAfter {
   test("temp checkpoint dir should be deleted if a query is stopped without errors") {
     import testImplicits._
     val query = MemoryStream[Int].toDS.writeStream.format("console").start()
+    query.processAllAvailable()
     val checkpointDir = new Path(
       query.asInstanceOf[StreamingQueryWrapper].streamingQuery.checkpointRoot)
     val fs = checkpointDir.getFileSystem(spark.sessionState.newHadoopConf())