Exchanging direct ByteBuffers between the dual JVMs

[JaroslavTulach]

Pull Request Description

• To effectively exchange huge chunks of memory among the "dual JVMs" ...
  • introduced by Use Dual JVM mode to run StdLib Native tests #13570
• ... as needed by In-Memory table implementations, let's rely on direct byte buffers
• with this PR we have a way for the two "dual JVMs" to exchange and share the same chunk of memory

Important Notes

• care must be taken to work properly with GC & free
• holding just the ByteBuffer instance doesn't prevent other JVM to GC and release its memory region
• holding a pointer to the original Value object while working with the ByteBuffer should be enough to prevent GC

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• All code follows the
  Scala,
  Java,
• Unit tests have been written where possible.