HDFS-10748. TestFileTruncate#testTruncateWithDataNodesRestart runs sometimes timeout. Contributed by Yiqun Lin.

(cherry picked from commit 4da5000dd33cf013e7212848ed2c44f1e60e860e)

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

@@ -699,6 +699,9 @@ public void testTruncateWithDataNodesRestart() throws Exception {
     assertEquals(newBlock.getBlock().getGenerationStamp(),
         oldBlock.getBlock().getGenerationStamp() + 1);
 
+    Thread.sleep(2000);
+    // trigger the second time BR to delete the corrupted replica if there's one
+    cluster.triggerBlockReports();
     // Wait replicas come to 3
     DFSTestUtil.waitReplication(fs, p, REPLICATION);
     // Old replica is disregarded and replaced with the truncated one