8129559: JShell: compilation fails if class, method or field is annotated and has modifiers
8080354: JShell: Runtime visible annotations cannot be retrieved
Reviewed-by: jlahoda

8167643: JShell: silently ignore access modifiers (as semantically irrelevant)
Reviewed-by: jlahoda

8134254: JShell API/tool: REPL for Java into JDK9
Summary: Adding the implementation of the jshell (read-eval-print-loop) tool.
Reviewed-by: briangoetz, mcimadamore, psandoz, forax
Contributed-by: robert.field@oracle.com, bitterfoxc@gmail.com, jan.lahoda@oracle.com