Spring Security AnonymousAuthenticationFilter should cache its Supplier<SecurityContext>

The Supplier<SecurityContext> in AnonymousAuthenticationFilter gets invoked several times on each request. Essentially, any time getContext is invoked downstream of it. While each call is quick, it seems a bit wasteful.

One way to cache it would be SingletonSupplier

Comment From: evgeniycheban

Hey, @jzheaux I can work on this.