Missing --add-exports for the tests

[pgrt]

Dear developers,

I am a Debian developer, currently packaging ed25519-java in Debian.

During my packaging process, I stumbled upon errors raised by the surefire plugin because (e.g.)
java.lang.IllegalAccessError: class net.i2p.crypto.eddsa.EdDSAEngineTest (in unnamed module @0x5d5baec3) cannot access class sun.security.util.DerValue (in module java.base) because module java.base does not export sun.security.util to unnamed module @0x5d5baec3
at net.i2p.crypto.eddsa.EdDSAEngineTest.testVerifyX509PublicKeyInfo(EdDSAEngineTest.java:227)

I could handle such errors thanks to the following patch. I hope it can be useful to you one day (obviously you did not encounter the issue up to now). I think it is linked to using OpenJDK-17 as the JDK.

Best,

--
Pierre

add-opens_in_test.txt