HDFS-14189. Fix intermittent failure of TestNameNodeMetrics. Contributed by Ayush Saxena.

(cherry picked from commit 1a08302897bac18baf0f56b7d41ad54f63ae191b)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/metrics/TestNameNodeMetrics.java

@@ -473,7 +473,7 @@ public class TestNameNodeMetrics {
 
     verifyZeroMetrics();
     verifyAggregatedMetricsTally();
-
+    BlockManagerTestUtil.stopRedundancyThread(bm);
     // Corrupt first replica of the block
     LocatedBlock block = NameNodeAdapter.getBlockLocations(
         cluster.getNameNode(), file.toString(), 0, 1).get(0);
@@ -562,7 +562,7 @@ public class TestNameNodeMetrics {
 
     verifyZeroMetrics();
     verifyAggregatedMetricsTally();
-
+    BlockManagerTestUtil.stopRedundancyThread(bm);
     // Corrupt first replica of the block
     LocatedBlocks lbs = fs.getClient().getNamenode().getBlockLocations(
         ecFile.toString(), 0, fileLen);