Thread.sleep() in StatisticsCollector (#4588)

Summary:
In  'StatisticsCollector', the call of Thread.sleep() might be better outside the loop?
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4588

Differential Revision: D12903406

Pulled By: sagar0

fbshipit-source-id: 1647ed779e9972bc2cea03f4c38e37ab3ad7c361

java/src/main/java/org/rocksdb/StatisticsCollector.java

@@ -93,9 +93,9 @@ public class StatisticsCollector {
                   statsCallback.histogramCallback(histogramType, histogramData);
                 }
               }
-
-              Thread.sleep(_statsCollectionInterval);
             }
+
+            Thread.sleep(_statsCollectionInterval);
           }
           catch (final InterruptedException e) {
             Thread.currentThread().interrupt();