RFR 8210596: jshell does not support raw string literals

[Robert Field]

Please review fix for:

     https://bugs.openjdk.java.net/browse/JDK-8210596

Webrev:

     http://cr.openjdk.java.net/~rfield/8210596v0.webrev/

Note: there were two issues:

(1) a logging set-up issue that caused the reported error; and

(2) needed handling for multi-line raw strings.

Thanks,
Robert