Fail more explicitly when AOT attempts to handle a bean definition that uses an instance supplier

[snicoll]

As revealed by #29555, we should throw a more tailored exception when a bean definition uses an instance supplier. If one is set, the container must honor it and there's no way for us to inspect it to generate the appropriate code.

[sdeleuze]

While working on this, I found that the current behavior is that instance suppliers on bean definition where the bean class has a default constructor are just ignored. Boot is implicitly leveraging this behavior, see spring-projects/spring-boot#33763 for more details.

Boot and other Spring portfolio projects should probably stop using instance supplier as a first step, and then we should throw an error during AOT processing (potentially in BeanDefinitionMethodGenerator constructor).

[sdeleuze]

Draft commit available at https://github.com/sdeleuze/spring-framework/tree/gh-29556.