RFR 8166744: JShell: java.lang.IndexOutOfBoundsException for legal history access

[ShinyaYoshida]

Hi,
Could you review this?

Bugs: https://bugs.openjdk.java.net/browse/JDK-8166744

Webrevs are here:
    jdk(fix):
http://cr.openjdk.java.net/~shinyafox/kulla/8166744/webrev.00.jdk/
    langtools(test):
http://cr.openjdk.java.net/~shinyafox/kulla/8166744/webrev.00.langtools/

Regards,
shinyafox(Shinya Yoshida)