8223537: testlibrary_tests/ctw/ClassesListTest.java fails with Agent timeout frequently

Reviewed-by: thartmann, kvn

src/share/vm/compiler/compileBroker.cpp

@@ -753,8 +753,8 @@ CompileTask* CompileQueue::get() {
   }
   if (task != NULL) {
     remove(task);
-    purge_stale_tasks(); // may temporarily release MCQ lock
   }
+  purge_stale_tasks(); // may temporarily release MCQ lock
   return task;
 }