Update `SpringFactoriesLoader` so that it can load files from
arbitrary locations. An instance of the loader class itself is now
returned from static factory methods that accept different
locations.
The recent `ArgumentResolver` and `FailureHandler` `loadFactories`
variants are now no longer available as static methods. They are
still available as instance methods.
The `loadFactories` static method remains to provide
back-compatibility with Spring Framework 5.x
See gh-28416
58c441f961