RFR (s) 8080352: jshell tool: Error message for using "package" should be more descriptive than "Failed"

[Robert Field]

"package xyz;" is illegal in JShell but was not being processed 
correctly because the JavacParser processing of package was left in.
Code deletion!

Bug:
     https://bugs.openjdk.java.net/browse/JDK-8080352

Webrev:
     http://cr.openjdk.java.net/~rfield/8080352v0.webrev/

Thanks,
Robert