Relaxed sandbox prototyping

[David Simms]

Since we are doing early prototyping, we have some partially document 
Java packages and partially implemented features. This has caused some 
trouble with stricter options used in JDK9. So for the Panama sandbox:

  * Doclint for Java compiling has been disabled (Werror is still in
    effect).
  * Also continuous testing (carried out by Oracle) has been reduced to
    Linux and MacOS on X86_64 only.
      o Other platforms may compile but not run.

This will allow for throw-away prototypes with minimal effort.

Cheers
/David Simms