RFR JDK-8171385: jshell tool: unresponsive to ctrl-C in input wait on Windows

[Jan Lahoda]

Hi,

I'd like to ask for a review of a fix for:
https://bugs.openjdk.java.net/browse/JDK-8171385

Webrev:
http://cr.openjdk.java.net/~jlahoda/8171385/webrev.00/

The problem is that the state of the StopDetectingInputStream changes 
while it is waiting for data. And when the first character read is 
Ctrl-C, the cancel might be sent the wrong direction. The proposed fix 
is to check the state again after reading from the input.

Jan