HDFS-16996. Fix flaky testFsCloseAfterClusterShutdown in TestFileCreation (#5697). Contributed by Nishtha Shah.

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java

@@ -92,6 +92,7 @@ import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.Time;
 import org.junit.Assert;
 import org.junit.Test;
+import org.mockito.Mockito;
 import org.slf4j.event.Level;
 
 /**
@@ -285,6 +286,7 @@ public class TestFileCreation {
       }, 1, 6000);
 
     } finally {
+      Mockito.reset(spyNamesystem);
       cluster.shutdown();
     }
   }