Fix beanResolver missing in CurrentSecurityContextArgumentResolver.

[happier233]

CurrentSecurityContextArgumentResolver has 'beanResolver' property, but never used. I think it might be missed.
I test the AuthenticationPrincipal annotation and CurrentSecurityContext annotation, CurrentSecurityContext annotation expression cannot work with bean.

[pivotal-issuemaster]

@happier233 Please sign the Contributor License Agreement!

Click here to manually synchronize the status of this Pull Request.

See the FAQ for frequently asked questions.

[pivotal-issuemaster]

@happier233 Thank you for signing the Contributor License Agreement!

[jzheaux]

Nice catch, @happier233! Would you please add a test that demonstrates that beanResolver is now getting used?

[jzheaux]

@happier233 are you able to make the requested changes to your PR?

[happier233]

@jzheaux I'm very sorry for costing many days to add the test to the PR, but I don't know where the code in my PR caused the format error.

[jzheaux]

No problem, @happier233. I've merged your changes in 873b9bd and polished it in 107f38f.

In the future, you can run ./gradlew format to update the formatting in your changes.