HDFS-17706. TestBlockTokenWithDFSStriped fails due to closed streams. (#7275). Contribtued by Felix N.

Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockTokenWithDFS.java

@@ -582,6 +582,9 @@ public class TestBlockTokenWithDFS {
 
     // restart the namenode to allow DFSClient to re-fetch tokens
     cluster.restartNameNode(0);
+    // Reopen closed streams
+    in1 = fs.open(fileToRead);
+    in3 = fs.open(fileToRead);
     // verify blockSeekTo() works again (by transparently re-fetching
     // tokens from namenode)
     in1.seek(0);