Migrate tests to JUnit5

[strangelookingnerd]

Most of the tests already use JUnit5. This PR will migrate the missing tests and remove the junit-jupiter-vintage as well as junit dependencies.

Migration includes:

• Using JUnit5 annotations
• Using Assertions
• Remove public modifiers from test classes and methods
• Clean up assertions (switching expected and actual, simplyifing assertions...)
• Trivial code cleanup

I validated my changes using ./build -t.

Checklist

• Make sure there is a GitHub_issue field for the change.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[wcy666103]

LGTM

[wcy666103]

Test locally first.

[strangelookingnerd]

Test locally first.

Seems like I missed that one, sorry for that. However to me it seems like this test should have failed without my changes as well.

I noticed that there is an exact copy of the failing test which has the assertion that is causing the issue here is commented out

Comparing
dubbo-spring-boot/src/test/java/org/apache/dubbo/spring/boot/env/DubboDefaultPropertiesEnvironmentPostProcessorTest.java

dubbo-spring-boot-autoconfigure/src/test/java/org/apache/dubbo/spring/boot/env/DubboDefaultPropertiesEnvironmentPostProcessorTest

---

Edit:

I just confirmed that the test that is failing was simply not executed before my changes. Digging a little deeper I found #12861 which suggests that the property that is checked here caused some kind of issue. I therefore propose to give the test the same treatment as in dubbo-spring-boot and comment the assertion out.