[SPARK-13166][SQL] Rename DataStreamReaderWriterSuite to DataFrameReaderWriterSuite

A follow up PR for #11062 because it didn't rename the test suite.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #11096 from zsxwing/rename.

sql/core/src/test/scala/org/apache/spark/sql/streaming/DataStreamReaderSuite.scala → sql/core/src/test/scala/org/apache/spark/sql/streaming/DataFrameReaderWriterSuite.scala

@@ -56,7 +56,7 @@ class DefaultSource extends StreamSourceProvider with StreamSinkProvider {
   }
 }
 
-class DataStreamReaderWriterSuite extends StreamTest with SharedSQLContext {
+class DataFrameReaderWriterSuite extends StreamTest with SharedSQLContext {
   import testImplicits._
 
   test("resolve default source") {