HDFS-13557. TestDFSAdmin#testListOpenFiles fails on Windows. Contributed by Anbang Hu.

(cherry picked from commit 6b67161ca33881d5f3d7606a57786e9c960759a1)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestDFSAdmin.java

@@ -796,12 +796,14 @@ public class TestDFSAdmin {
     if (closedFileSet != null) {
       for (Path closedFilePath : closedFileSet) {
         assertThat(outStr,
-            not(containsString(closedFilePath.toString() + "\n")));
+            not(containsString(closedFilePath.toString() +
+                System.lineSeparator())));
       }
     }
 
     for (Path openFilePath : openFilesMap.keySet()) {
-      assertThat(outStr, is(containsString(openFilePath.toString() + "\n")));
+      assertThat(outStr, is(containsString(openFilePath.toString() +
+          System.lineSeparator())));
     }
   }