LRUListWithAsyncSorting.createExecutor needs to configure ThreadFactory and ThreadGroup

The new LRUListWithAsyncSorting.createExecutor does not configure thread names nor a thread group. The ThreadGroup is important so that unhandled exceptions in these threads will be logged.
The thread names help in debugging stack dumps.
Also, these threads are currently non-daemon so they could cause the shutdown of the JVM to hang.