IdleRemover is a singleton, with only one static instance. This single instance creates a thread that asks the InternalManagedConnectionPool to remove its timed out connections.

If the pool's timeout is not zero, the InternalManagedConnectionPool registers itself with the IdleRemover.

All InternalManagedConnectionPools share the same IdleRemover.

Calls InternalManagedConnectionPool.removeTimedOut()