Add support for JUnit6

[schulzjo-tng]

• Check if [part2]add support JUnit 6.x testing framework.  #1658 covers anything not covered here
• Consider cleaning up commit history

[arukiidou]

Part 1 and Part 2 are almost identical.
If possible, I　recommend cherry-picking from Part 2.

Only the following three things should be different:

• It starts over again from the addition of the shared tests
• The commits have been split into smaller ones to make things easier
• example-test has been added