HDFS-7612: Fix default cache directory in TestOfflineEditsViewer.testStored. Contributed by Michael Kuchenbecker (#3571)

(cherry picked from commit a73ff6915ae3e0ced1b4c814a94845f51e655a0c)

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

@@ -163,7 +163,7 @@ public class TestOfflineEditsViewer {
   public void testStored() throws IOException {
     // reference edits stored with source code (see build.xml)
     final String cacheDir = System.getProperty("test.cache.data",
-        "build/test/cache");
+        "target/test-classes");
     // binary, XML, reparsed binary
     String editsStored = cacheDir + "/editsStored";
     String editsStoredParsedXml = cacheDir + "/editsStoredParsed.xml";