RFR: 8154436: Drop code to support Windows XP in windows async channel impl

[Alan Bateman]

On 18/04/2016 12:05, Claes Redestad wrote:
> Hi,
>
> this patch removes Iocp.supportsThreadAgnosticIo since this is now 
> true for all supported versions of windows.
>
> bug: https://bugs.openjdk.java.net/browse/JDK-8154436
> webrev: http://cr.openjdk.java.net/~redestad/8154436/webrev.01/
This looks good.

-Alan