RFR 8179856: jshell tool: not suitable for pipeline use

[Robert Field]

Please review --

Bugs:

     8179856: jshell tool: not suitable for pipeline use
     https://bugs.openjdk.java.net/browse/JDK-8179856

     8186708: jshell tool: bad load file garbles message and does not abort
     https://bugs.openjdk.java.net/browse/JDK-8186708

Webrev:

     http://cr.openjdk.java.net/~rfield/8179856v1.webrev/

Thanks,
Robert