Small - PLEASE Review: RFR JShell: NPE in translateExceptionStack and /help /help

[Steven Schlansker]

In particular we were excited to use JShell but could not present it to internal customers
while stack traces involving Proxy objects (which we use extensively) cause JShell to crash.

We are still looking forward to using JShell more extensively once JDK-8210527 is solved.
Thank you Robert and whoever ends up reviewing the changes!

> On Dec 11, 2019, at 1:42 PM, Robert Field <robert.field at oracle.com> wrote:
> 
> Today is last day for one of these.
> 
> Thanks,
> Robert
> 
> On 12/6/19 6:54 PM, Robert Field wrote:
>> Please review ...
>> 
>> Bugs:
>> 
>> https://bugs.openjdk.java.net/browse/JDK-8210527
>> 
>> https://bugs.openjdk.java.net/browse/JDK-8232855
>> 
>> Webrev:
>> 
>> http://cr.openjdk.java.net/~rfield/8210527v1.webrev/
>> 
>> 
>> Thanks,
>> Robert
>>