Introduce `getName()` in SpEL's `BeanReference`

[sbrannen]

Overview

Several SpelNodeImpl implementations provide direct access to the associated property name, field name, method name, etc. For example, see MethodReference and PropertyOrFieldReference.

For convenience, we should also make the bean name available in BeanReference.

Related Issues

• Provide Native Hints for Beans used in Method Security Annotations spring-security#14652