cygwin: recognize EOF on named pipe closure
cygwin: recognize EOF on named pipe closure

On Cygwin a named pipe closed by terminating a child process
may be reported via `ECONNRESET` on the next read.  Teach
`uv__read` to interpret this as end of file.

This fixes the `spawn_and_kill_with_std` test.

PR-URL: https://github.com/libuv/libuv/pull/1312
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <3f17e29e343c4cf8809fb0970d81d6d8ee88d6b3@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso