Goint toward OpenJDK 17 compatibility

[pgrt]

Hello,

capsule is packaged in Debian, where we are currently checking if building packages is still possible with OpenJDK 17, whereas we currently use OpenJDK 11. Hence the bug report https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1011924 concerning capsule. The current pull request solves the issue in the bug, but then I get 40 failing tests, please see the enclosed log. failingTests_openJDK17_20220529.txt

I guess there are various reasons why the tests fail, for instance testWrapperCapsuleAgent certainly fails because of the illegal reflective access attempt in CapsuleTestUtils.accessible (which "only" issued a warning with previous JDKs). For other tests, I admit I have not gone into details that much.

I will be happy to provide you with more details if I can and I would appreciate any help to achieve OpenJDK 17 compatibility if you have time for it,

Best, Pierre