Adding J9 sys thread to known threads. Interesting what this is triggered by (I can make it happen by calling mgmnt factory directly).

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1372301 13f79535-47bb-0310-9956-ffa450edef68

lucene/test-framework/src/java/org/apache/lucene/util/QuickPatchThreadsFilter.java

@@ -30,6 +30,12 @@ public class QuickPatchThreadsFilter implements ThreadFilter {
     if (t.getName().equals("AWT-AppKit")) {
       return true;
     }
+
+    // J9 memory pool thread.
+    if (t.getName().equals("MemoryPoolMXBean notification dispatcher")) {
+      return true;
+    }
+
     return false;
   }
 }