Amend HBASE-20646 TestWALProcedureStoreOnHDFS failing on branch-1

Suppress error-prone false positive

hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestWALProcedureStoreOnHDFS.java

@@ -106,6 +106,7 @@ public class TestWALProcedureStoreOnHDFS {
   }
 
   // No @After
+  @SuppressWarnings("JUnit4TearDownNotRun")
   public void tearDown() throws Exception {
     store.stop(false);
     UTIL.getDFSCluster().getFileSystem().delete(store.getWALDir(), true);