RFR: JDK-8166535: jshell tool: cannot handle non-ascii characters

[Jan Lahoda]

Hi,

This is a basic patch to handle non-ASCII characters on Windows. The 
main change is use of ReadConsoleInputW instead of the current 
ReadConsoleInput. This should ensure the read characters are Unicode as 
opposed to current ASCII.

So, if a non-ASCII character is typed, and is supported by the default 
encoding and the console output encoding, it should work.

If the character is not supported by the default encoding, it will still 
be turned into '?'. AFAIK, this is consistent with JLine behavior (the 
code patched here is our replacement for jansi used by JLine). This 
differs from System.in behavior, where the unsupported characters with 
diacritics are converted to equivalent characters without diacritics. I 
think we could try to improve that in the future (I did some 
experiments, but the results were not perfect so far).

For Linux, I am afraid I didn't see the problem there - I'll file a 
separate bug to investigate.

Bug: https://bugs.openjdk.java.net/browse/JDK-8166535
Webrev:
http://cr.openjdk.java.net/~jlahoda/8166535/webrev.00/

Thanks,
     Jan