Steps towards integrating Kulla into JDK9

[Robert Field]

I have just pushed a change that moves the Kulla source and test files 
into their designated places in the langtools directory structure.

The module is jdk.eval -- so the source files can be found under 
src/jdk.eval/

The source packages are:
     API:                        jdk.eval
     implementation:    jdk.internal.eval.impl and 
jdk.internal.eval.impl.remote
     REPL tool:              jdk.internal.eval.jshell

The latter is up for debate.  Brian suggested the name jshell for the 
REPL tool, the more it has sat in my head the more I like it, there is 
nothing cognitively nor linguistically natural about REPL.

The tests have been moved to test/jdk/eval
I have flatten the one stress test into this.

The idea is to have the normal make scripts also build Kulla.  This does 
not currently work, a "make images" falls over almost immediately.  
Anyone with experience that can help with this, please step forward.  
Note: part of what needs to happen is that jline need to be rolled into 
the JDK; Though this is not the immediate failure.

For now, I have adjusted the old scripts to the new locations, so, 
repl/scripts/   compile.sh  run.sh test.sh still work when run from repl/

Thanks,
Robert