[TEST] Suppress exception in Watcher benchmark

Original commit: elastic/x-pack-elasticsearch@099cad0ac1

elasticsearch/x-pack/watcher/src/test/java/org/elasticsearch/watcher/test/bench/WatcherScheduleEngineBenchmark.java

@@ -169,9 +169,7 @@ public class WatcherScheduleEngineBenchmark {
                                     jvmUsedHeapSpace.inc(heapUsed.bytes());
                                     Thread.sleep(1000);
                                 }
-                            } catch (InterruptedException e) {
-                                e.printStackTrace();
-                            }
+                            } catch (InterruptedException ignored) {}
                         }
                     });
                     sampleThread.start();