[bug] sun.nio.ch.PipeImpl uses IPv4

[Matthias-Christian Ott]

Expected behaviour:

If you assume that sun.nio.ch.PipeImpl communicates over local TCP/IP
sockets, PipeImpl should open a socket on and connect to over localhost.

Actual behaviour:

sun.nio.ch.PipeImpl open a socket on and connects to 127.0.0.1.

Suggested fix:

sun.nio.ch.PipeImpl should use localhost instead of 127.0.0.1. RFC 6761
states that "[users] may assume that IPv4 and IPv6 address queries for
localhost names will always resolve to the respective IP loopback
address". This assumption is correct on all supported versions of
Microsoft Windows (in non-broken configurations).