It is possible to fetch an uninitialized Bean when cycling dependencies

[nineya]

Following up on the latest comments in #25667，Due to the lack of thread-safe judgment for earlySingletonObjects in the getSingleton(String beanName, boolean allowEarlyReference) method, the method may return an uninitialized Bean. And without any processing thereafter, spring returns the uninitialized bean directly to the client that calls the BeanFactory.getBean method.

[nineya]

Screenshot of the cause of the problem.

[snicoll]

There's no need to create both an issue and a PR as one superseded the other.