[Branch-4.16] Fix ReadOnlyLedgerHandle leak issue when checkAllLedgers (

#4469)

* Enhance the SimpleTestCommand test, make it cover more case.

* Fix ReadOnlyLedgerHandle leak issue when checkAllLedgers.

* code clean.

bookkeeper-server/src/main/java/org/apache/bookkeeper/replication/AuditorCheckAllLedgersTask.java

@@ -210,6 +210,7 @@ void checkAllLedgers() throws BKException, IOException, InterruptedException {
                             auditorStats.getNumFragmentsPerLedger().registerSuccessfulValue(lh.getNumFragments());
                             auditorStats.getNumBookiesPerLedger().registerSuccessfulValue(lh.getNumBookies());
                             auditorStats.getNumLedgersChecked().inc();
+                            lh.closeAsync();
                         });
                     } else if (BKException.Code.NoSuchLedgerExistsOnMetadataServerException == rc) {
                         if (LOG.isDebugEnabled()) {